SERIESSUM in ONLYOFFICE Spreadsheet Editor

• Introduced: Original introduction release is not established by the checked sources.
• Available: Listed in current unversioned ONLYOFFICE help, checked October 18, 2026.
• Implementation inspected: Official SDKJS v10.0.0.169, commit 3679e0375a758d7dc59d31337a45461be3525ed8. The snapshot does not prove identical behavior in every installed editor.
• Retired or deprecated: These sources do not establish retirement or formal deprecation.
• Testing: Numerical examples are independent mathematical expectations, and implementation discrepancies are labeled source predictions. No ONLYOFFICE application or calculation-engine execution was performed.

The examples use English function names and commas. Use your locale’s argument separator if different. Retain full precision in formulas; round only the displayed result. These examples establish only the stated mathematical or source-trace cases. Application rendering, array placement and general import/export behavior have not been tested.

=SERIESSUM(x, n, m, coefficients)

Exactly four arguments are registered. x is the evaluation point, n is the first exponent, m is the exponent increment, and coefficients supplies one coefficient per term. With coefficients a0,a1,…, the sum is a0*x^n + a1*x^(n+m) + a2*x^(n+2*m) + ....

The number of supplied coefficients determines the finite number of terms. SERIESSUM does not infer an infinite series, add missing terms or determine a convergence region. n and m are numeric exponents/steps; they are not restricted to positive integer counts by the inspected body. The mathematical domain still matters, especially for negative x and fractional powers.

1. Put 1 in A1, −2 in A2 and 3 in A3.
2. Evaluate =SERIESSUM(2,0,1,A1:A3).
3. Independently expand the three terms: 1×2⁰, −2×2¹ and 3×2².
4. Their sum is 1−4+12 = 9.

Changing n and m changes every exponent. =SERIESSUM(2,1,2,A1:A3) uses exponents 1,3,5 and gives 2−16+96 = 82. The coefficient values have not changed; the power schedule has.

A scalar coefficient is also supported. =SERIESSUM(2,3,1,5) has one term, 5×2³ = 40. With only one term, m does not affect its value because there is no later exponent to advance to.

The inspected array/range loop reads coefficients row by row. On a fresh sheet enter rows 1,2 and 3,4 in A1:B2. =SERIESSUM(2,0,1,A1:B2) uses coefficient sequence 1,2,3,4, producing 1+4+12+32 = 49.

Reading those cells down columns would instead create another polynomial. For clarity, keep coefficients in one explicitly ordered column or row unless the rectangular traversal is intentional. A zero coefficient keeps its term’s exponent position; it is not the same as removing that coefficient and shifting every later exponent.

Enter coefficients 1, −0.5 and =1/24 in A1:A3. Then =SERIESSUM(0.5,0,2,A1:A3) evaluates 1-x²/2+x⁴/24 at x=0.5 radians. The independent exact value is 337/384 ≈ 0.877604166667.

The actual cosine of 0.5 radians is approximately 0.877582561890, so this three-term polynomial differs by about 0.0000216047763. The difference is truncation error from stopping the mathematical expansion, not evidence that SERIESSUM calculated its finite polynomial incorrectly.

Keep the input unit consistent with the series derivation. This approximation uses radians, not degrees. Adding another term requires its correct coefficient and exponent position, not just extending the selected range into a blank cell. For applications where approximation error matters, bound or measure that error separately from spreadsheet rounding.

A genuinely empty coefficient element predicts internal not_available, conventionally #N/A; it is not silently treated as zero. A Boolean coefficient element predicts wrong_value_type (#VALUE!). Existing error elements in a coefficient range propagate. Numeric text in a coefficient range is passed through numeric conversion, whereas a direct scalar text coefficient is rejected by the scalar dispatch. Use numeric coefficient cells to avoid these path differences.

The inspected first three arguments reject empty values as #N/A and Boolean values as #VALUE!; ordinary conversion errors propagate. Multi-cell ranges used for x, n or m are not general vectorized inputs in this path. A one-cell reference is clearer when those parameters live on the sheet.

In the coefficient-array path, a power calculation producing NaN is explicitly replaced by zero. For example, negative x with fractional exponents can therefore make mathematically undefined real-power terms contribute zero. =SERIESSUM(-1,0.5,1,A1:A2) with coefficients 1 and 2 is source-predicted to return 0 because both powers are non-real in ordinary real arithmetic.

That result does not make the series mathematically valid. The scalar-coefficient path does not contain the same replacement, so replacing a single coefficient range with a scalar may change invalid-domain behavior. Avoid negative bases with noninteger exponents unless the intended domain and implementation behavior have been explicitly resolved. Infinite intermediate values and very large cancelling terms can also exceed useful numerical precision.

Retain the coefficient list and exponent rule beside an important calculation. A plausible numeric result is not sufficient to prove that the selected range, order or mathematical domain matches the intended series.

Recalculate representative formulas when moving a workbook between editors. Matching names do not guarantee identical argument coercion, array behavior, numerical precision or error handling. These source-derived examples do not establish automatic spill behavior or a general import/export guarantee.

• POWER
• COS
• SUM

• ONLYOFFICE SERIESSUM help, checked October 18, 2026.
• Official SDKJS implementation, 5355–5506, tag v10.0.0.169 and exact commit above.