OFFSET
1,3
COMMENTS
Alternatively, if n = prime(i_1) * ... * prime(i_k), then a(n) is the denominator of 1/i_1! + ... + 1/i_k!.
LINKS
Robert Israel, Table of n, a(n) for n = 1..3168
MAPLE
f:= proc(n) local F, t;
F:= ifactors(n)[2];
denom(add(t[2]/numtheory:-pi(t[1])!, t=F))
end proc:
map(f, [$1..100]); # Robert Israel, Oct 13 2024
MATHEMATICA
Table[Total[Cases[If[n==1, {}, FactorInteger[n]], {p_, k_}:>k/PrimePi[p]!]], {n, 100}]//Denominator
CROSSREFS
KEYWORD
AUTHOR
Gus Wiseman, May 18 2019
STATUS
approved