OFFSET
0,3
LINKS
Amiram Eldar, Table of n, a(n) for n = 0..3000
MATHEMATICA
f[p_, e_] := 2^DigitCount[e, 2, 1]; a[0] = a[1] = 1; a[n_] := Times @@ f @@@ FactorInteger[n!]; Array[a, 100, 0]
PROG
(PARI) a(n) = vecprod(apply(x -> 2^hammingweight(x), factor(n!)[, 2]));
(Python)
from collections import Counter
from sympy import factorint
def A375635(n): return 1<<sum(e.bit_count() for e in sum((Counter(factorint(i)) for i in range(2, n+1)), start=Counter()).values()) # Chai Wah Wu, Aug 22 2024
CROSSREFS
KEYWORD
nonn
AUTHOR
Amiram Eldar, Aug 22 2024
STATUS
approved