OFFSET
0,4
LINKS
N. J. A. Sloane, Transforms.
PROG
(PARI) f(n) = my(m=1); while ((m*(m+1))%n, m++); m; \\ A344005
a(n) = sumdiv(n, d, moebius(n/d)*f(d)); \\ Michel Marcus, Aug 19 2021
CROSSREFS
KEYWORD
sign
AUTHOR
N. J. A. Sloane, Aug 18 2021
STATUS
approved