A134007 a(n) = 1^n + 3^n + 5^n + 7^n + 9^n.
5, 25, 165, 1225, 9669, 79225, 665445, 5686825, 49208709, 429746905, 3779084325, 33407391625, 296515495749, 2639977136185, 23561123826405, 210669225531625, 1886405750358789, 16910575282247065, 151726863979595685
Offset: 0
Examples
a(3)=165 because 1^2 + 3^2 + 5^2 + 7^2 + 9^2 = 165.
Links
- Vincenzo Librandi, Table of n, a(n) for n = 0..300
- T. A. Gulliver, Divisibility of sums of powers of odd integers, Int. Math. For. 5 (2010) 3059-3066, eq. 6.
- Index entries for linear recurrences with constant coefficients, signature (25, -230, 950, -1689, 945).
Programs
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Magma
[1^n + 3^n + 5^n + 7^n + 9^n: n in [0..20]]; // Vincenzo Librandi, Jun 20 2011
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Mathematica
Table[1^n+3^n+5^n+7^n+9^n,{n,0,30}]
Formula
a(n) = 24*a(n-1) - 206*a(n-2) + 744*a(n-3) - 945*a(n-4) + 384.
G.f.: -(5 - 100*x + 690*x^2 - 1900*x^3 + 1689*x^4)/((-1+x)*(3*x-1)*(9*x-1)*(7*x-1)*(5*x-1)). - R. J. Mathar, Nov 14 2007