OFFSET
1,6
LINKS
Alois P. Heinz, Table of n, a(n) for n = 1..20000
MAPLE
a:= proc(n) option remember; `if`(n<1, 0,
a(n-1)+numtheory[mobius](n*(n+1)))
end:
seq(a(n), n=1..100); # Alois P. Heinz, Apr 17 2021
MATHEMATICA
Accumulate @ Table[MoebiusMu[n] * MoebiusMu[n+1], {n, 1, 100}] (* Amiram Eldar, Jul 26 2022 *)
PROG
(PARI) a(n) = sum(i=1, n, moebius(i*(i+1))); \\ Michel Marcus, Jul 26 2022
CROSSREFS
KEYWORD
sign
AUTHOR
N. J. A. Sloane, Dec 12 2019
STATUS
approved