A054606 a(n) = Sum_{d|7} phi(d)*n^(7/d).

0, 7, 140, 2205, 16408, 78155, 279972, 823585, 2097200, 4783023, 10000060, 19487237, 35831880, 62748595, 105413588, 170859465, 268435552, 410338775, 612220140, 893871853, 1280000120, 1801088667, 2494358020, 3404825585

Offset: 0

Author

N. J. A. Sloane, Apr 16 2000

Keywords

• nonn
• easy

Links

• Seiichi Manyama, Table of n, a(n) for n = 0..10000
• Index entries for linear recurrences with constant coefficients, signature (8,-28,56,-70,56,-28,8,-1).

Crossrefs

Row n=7 of A185651.

Formula

a(n) = n^7 + 6n.

G.f.: 7*x*(x^6+12*x^5+183*x^4+328*x^3+183*x^2+12*x+1) / (x-1)^8. [Colin Barker, Dec 21 2012]