@AvivSH no need to know the code of SERIESSUM, it is a math function of excel, google sheets, open office, and libre office. YouTube has videos about SERIESSUM for trigonometric functions, hyperbolic functions, Legendre Polynomials, Bessel Polynomials, BESSELJ, BESSELI, Chebyshev Polynomials, Hermite Polynomials and Laguerre Polynomials. It can be used to generate Pascal Triangle Coefficients using COMBIN, COMBINA, and PERMUTE functions.
