A074533 a(n) = 2^n + 4^n + 6^n.
3, 12, 56, 288, 1568, 8832, 50816, 296448, 1745408, 10340352, 61515776, 366993408, 2193563648, 13127811072, 78632615936, 471258759168, 2825404940288, 16943839444992, 101628676407296, 609634618441728
Offset: 0
Links
- Vincenzo Librandi, Table of n, a(n) for n = 0..200
- T. A. Gulliver, Sums of Powers of Integers Divisible by Three, Int. J. Contemp. Math. Sciences, Vol. 7, 2012, no. 38, pp. 1895-1901. - From _N. J. A. Sloane_, Dec 22 2012
- D. Suprijanto and Rusliansyah, Observation on Sums of Powers of Integers Divisible by Four, Applied Mathematical Sciences, Vol. 8, 2014, no. 45, 2219-2226.
- Index entries for linear recurrences with constant coefficients, signature (12,-44,48).
Programs
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Magma
[2^n + 4^n + 6^n: n in [0..25]]; // Vincenzo Librandi, Jun 11 2011
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Mathematica
Table[2^n + 4^n + 6^n, {n, 0, 20}]
Formula
G.f.: 1/(1-2*x)+1/(1-4*x)+1/(1-6*x). E.g.f.: exp(2*x)+exp(4*x)+exp(6*x). - Mohammad K. Azarian, Dec 27 2008