A188526 - OEIS

A188526

a(n) = 3^(2*n + 3) + 2^n.

28, 245, 2191, 19691, 177163, 1594355, 14348971, 129140291, 1162261723, 10460353715, 94143179851, 847288611491, 7625597489083, 68630377373075, 617673396300331, 5559060566588291, 50031545099065243, 450283905891128435, 4052555153019238411

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OFFSET

0,1

COMMENTS

All terms are multiples of 7: A082784(a(n)) = 1, A188527(n) = a(n)/7.

REFERENCES

Kees Doets and Jan van Eijck, The Haskell Road to Logic, Maths and Programming, The King's College Publications, London 2006. Cf. exercise 7.9, p 239.

LINKS

Vincenzo Librandi, Table of n, a(n) for n = 0..500

Index entries for linear recurrences with constant coefficients, signature (11, -18).

FORMULA

a(n) = A013708(n+1) + A000079(n).

G.f.: 7*(4-9*x)/((1-2*x)*(1-9*x)). - Bruno Berselli, Jul 17 2011

MATHEMATICA

Table[3^(2n+3)+2^n, {n, 0, 20}] (* Harvey P. Dale, Apr 09 2011 *)

PROG

(Magma) [3^(2*n + 3) + 2^n: n in [0..20]]; // Vincenzo Librandi, Jul 17 2011

CROSSREFS

Cf. A000079, A013708, A082784, A188527.