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A176818 a(n) = (3^(2*n+1) + 2^(n+2))/7. 0
1, 5, 37, 317, 2821, 25325, 227797, 2049917, 18448741, 166037645, 1494336757, 13449026717, 121041232261, 1089371073965, 9804339632917, 88239056630717, 794151509545381, 7147363585646285, 64326272270292277, 578936450431581917 (list; graph; refs; listen; history; text; internal format)
OFFSET

0,2

COMMENTS

3^(2*n+1) + 2^(n+2) = 3*(3^2)^n + 4*2^n == 3*2^n + 4*2^n = 7*2^n == 0 (mod 7).

LINKS

Table of n, a(n) for n=0..19.

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

FORMULA

G.f.: ( 1-6*x ) / ( (9*x-1)*(2*x-1) ). - R. J. Mathar, Feb 18 2016

EXAMPLE

a(2) = (3^5 + 2^4)/7 = 259/7 = 37.

MAPLE

a:= n-> (3^(2*n+1) + 2^(n+2))/7:

seq (a(n), n=0..30);

CROSSREFS

Sequence in context: A208675 A084212 A323219 * A068785 A199562 A246540

Adjacent sequences:  A176815 A176816 A176817 * A176819 A176820 A176821

KEYWORD

nonn,easy

AUTHOR

Michel Lagneau, Apr 26 2010

STATUS

approved

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Last modified October 28 16:41 EDT 2021. Contains 348329 sequences. (Running on oeis4.)