2.1.920 Part 4 Section 3.17.7.25, BESSELK

a.   The standard uses the mathematical formula: K_n (x)= (p/2) i^(n+1) [ J_n (ix)+iY_n (ix) ], and does not say how function arguments map to formula variables.

Office uses the mathematical formula K_n (x)= (π/2) i^(n+1) [ J_n (ix)+iY_n (ix) ] and maps Jn to the J Bessel function, Yn to the Y Bessel function, n to argument n, and x to argument x.