OFFSET
1,6
COMMENTS
LINKS
Robert Israel, Table of n, a(n) for n = 1..10000
EXAMPLE
The prime signature of 13860 is (2,2,1,1,1), with multiplicities (2,3), so a(13860) = 6.
MAPLE
f:= proc(n) local M, s;
M:= ifactors(n)[2][.., 2];
mul(numboccur(s, M), s=convert(M, set));
end proc:
f(1):= 0:
map(f, [$1..100]); # Robert Israel, May 19 2023
MATHEMATICA
Table[If[n==1, 0, Times@@Length/@Split[Sort[Last/@FactorInteger[n]]]], {n, 100}]
Join[{0}, Table[Times@@(Length/@Split[FactorInteger[n][[;; , 2]]]), {n, 2, 100}]] (* Harvey P. Dale, Oct 20 2024 *)
PROG
(Python)
from math import prod
from itertools import groupby
from sympy import factorint
def A353507(n): return 0 if n == 1 else prod(len(list(g)) for k, g in groupby(factorint(n).values())) # Chai Wah Wu, May 20 2022
CROSSREFS
KEYWORD
nonn
AUTHOR
Gus Wiseman, May 19 2022
STATUS
approved