OFFSET
1,24
COMMENTS
LINKS
Antti Karttunen, Table of n, a(n) for n = 1..20000
MATHEMATICA
hwt[n_]:=Total[Cases[FactorInteger[n], {p_, k_}:>PrimePi[p] k]];
Table[DivisorSigma[0, n]-Length[Union[hwt/@Divisors[n]]], {n, 100}]
PROG
(PARI)
A299701(n) = { my(f = factor(n), pids = List([])); for(i=1, #f~, while(f[i, 2], f[i, 2]--; listput(pids, primepi(f[i, 1])))); pids = Vec(pids); my(sv=vector(vecsum(pids))); for(b=1, (2^length(pids))-1, sv[sumbybits(pids, b)] = 1); 1+vecsum(sv); }; \\ Not really an optimal way to count these.
sumbybits(v, b) = { my(s=0, i=1); while(b>0, s += (b%2)*v[i]; i++; b >>= 1); (s); }; \\ Antti Karttunen, May 26 2019
CROSSREFS
KEYWORD
nonn
AUTHOR
Gus Wiseman, May 23 2019
STATUS
approved