A073317 a(n)=Sum_{j = 0..n} binomial(phi(n),phi(j)).

2, 3, 6, 7, 22, 8, 74, 29, 90, 30, 1207, 31, 4118, 121, 466, 467, 67266, 122, 236984, 496, 7452, 1973, 3956273, 497, 1305399, 8014, 405387, 8015, 222108532, 498, 792121142, 127353, 1688345, 127354, 21495390, 8511, 66695906846, 486580

Offset: 1

Author

Labos Elemer, Jul 26 2002

Keywords

• easy
• nonn

Crossrefs

Cf. A066781, A073318.

Programs

Mathematica

g[x_] := EulerPhi[x] Table[Apply[Plus, Table[Binomial[g[n], g[j]], {j, 0, n}]], {n, 1, 50}]