A372661 a(n) = Sum_{i=1..n} Sum_{j=1..n} Sum_{k=1..n} phi(i*j*k).
1, 14, 98, 412, 1436, 3212, 8312, 17460, 34182, 57406, 107306, 161942, 277550, 406490, 581210, 850162, 1292018, 1701752, 2481476, 3216100, 4184464, 5406704, 7414512, 9119640, 11849180, 14736284, 18541664, 22500200, 28950168, 33410736, 42380976, 51166240, 60859420
Offset: 1
Keywords
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.
Programs
-
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 *) -
PARI
a(n) = sum(i=1, n, sum(j=1, n, sum(k=1, n, eulerphi(i*j*k))));