OFFSET
1,2
LINKS
Vaclav Kotesovec, Table of n, a(n) for n = 1..3930
Vaclav Kotesovec, Plot of a(n)^(1/n) for n = 1..10000
FORMULA
a(1) = 1; a(n) = Sum_{k = 1..n} a(lcm(n, k)/n).
a(1) = 1; a(n) = Sum_{d|n} Sum_{k = 1..d, gcd(d, k) = 1} a(k).
MAPLE
A333613:= proc(n) option remember;
if n<3 then n;
else add( A333613(lcm(n, j)/n), j = 1..n);
end if; end proc;
seq(A333613(n), n=1..40); # G. C. Greubel, Mar 08 2021
MATHEMATICA
a[1] = 1; a[n_] := a[n] = Sum[a[k/GCD[n, k]], {k, n}]; Table[a[n], {n, 37}]
a[1] = 1; a[n_] := a[n] = Sum[Sum[If[GCD[k, d] == 1, a[k], 0], {k, d}], {d, Divisors[n]}]; Table[a[n], {n, 37}]
PROG
CROSSREFS
KEYWORD
nonn
AUTHOR
Ilya Gutkovskiy, Mar 28 2020
STATUS
approved