OFFSET
1,2
COMMENTS
a(n) = 1+n^2*(n-1)^2/4 if n is prime. - Robert Israel, Apr 19 2021
LINKS
Robert Israel, Table of n, a(n) for n = 1..10000
FORMULA
a(n) = Sum_{d|n} A053819(d).
MAPLE
f:= proc(n) local k;
add((k/igcd(n, k))^3, k=1..n)
end proc:
map(f, [$1..100]); # Robert Israel, Apr 19 2021
MATHEMATICA
Table[Sum[(k/GCD[n, k])^3, {k, 1, n}], {n, 1, 44}]
PROG
(PARI) a(n) = sum(k=1, n, (k/gcd(n, k))^3); \\ Michel Marcus, Apr 17 2021
CROSSREFS
KEYWORD
nonn
AUTHOR
Ilya Gutkovskiy, Apr 17 2021
STATUS
approved