Function: sumdigits
Section: number_theoretical
C-Name: sumdigits0
Prototype: GDG
Help: sumdigits(n,{B=10}): sum of digits in the integer |n|, when written in
base B.
Doc: sum of digits in the integer $|n|$, when written in base $B > 1$.
\bprog
? sumdigits(123456789)
%1 = 45
? sumdigits(123456789, 2)
%1 = 16
@eprog\noindent Note that the sum of bits in $n$ is also returned by
\tet{hammingweight}. This function is much faster than
\kbd{vecsum(digits(n,B))} when $B$ is $10$ or a power of $2$, and only
slightly faster in other cases.
Variant: Also available is \fun{GEN}{sumdigits}{GEN n}, for $B = 10$.