OFFSET
1,1
LINKS
Antti Karttunen, Table of n, a(n) for n = 1..20000
FORMULA
MATHEMATICA
f1[p_, e_] := -2*(p - 1)^(e - 1); f2[p_, e_] := 2*(p + 1)^(e - 1); a[1] = 2; a[n_] := Times @@ f1 @@@ (f = FactorInteger[n]) + Times @@ f2 @@@ f; Array[a, 100] (* Amiram Eldar, Nov 16 2021 *)
CROSSREFS
KEYWORD
nonn
AUTHOR
Antti Karttunen, Nov 16 2021
STATUS
approved