OFFSET
1,2
LINKS
Vaclav Kotesovec, Table of n, a(n) for n = 1..1000
Vaclav Kotesovec, Plot of a(n)/n^6 for n = 1..1000
Eric Weisstein's World of Mathematics, Totient Function.
MATHEMATICA
Table[Sum[EulerPhi[i*j*k], {i, 1, n}, {j, 1, n}, {k, 1, n}], {n, 1, 40}] (* Vaclav Kotesovec, May 09 2024 *)
s = 1; Join[{1}, Table[s += Sum[EulerPhi[i*j*n], {i, 1, n}, {j, 1, n}] + Sum[EulerPhi[i*j*n], {i, 1, n - 1}, {j, 1, n}] + Sum[EulerPhi[i*j*n], {i, 1, n - 1}, {j, 1, n - 1}], {n, 2, 40}]] (* Vaclav Kotesovec, May 09 2024 *)
PROG
(PARI) a(n) = sum(i=1, n, sum(j=1, n, sum(k=1, n, eulerphi(i*j*k))));
CROSSREFS
KEYWORD
nonn
AUTHOR
Seiichi Manyama, May 09 2024
STATUS
approved