// zeta(s) = 1/(1-2^(1-s)) sum(n=0..infty, (-1)^n/(n+1)^s),
// with Cohen-Villegas-Zagier convergence acceleration.
var uintC actuallen = len+2; // 2 Schutz-Digits
// zeta(s) = 1/(1-2^(1-s)) sum(n=0..infty, (-1)^n/(n+1)^s),
// with Cohen-Villegas-Zagier convergence acceleration.
var uintC actuallen = len+2; // 2 Schutz-Digits