Some new GP features
harmonic
For large n, an approximate value can be computed with psi:
? harm(n,k) =
{
my(s=k-1);
(-1)^s*derivnum(x=0,psi(n+1+x)-psi(1+x),s)/s!;
}
? harm(100000,3)
%67 = 1.2020569031095947853972381615115333241
? harmonic(100000,3)*1.
%68 = 1.2020569031095947853972381615115333241