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A144479
a(0)=1, a(1)=3, a(n) = 8*a(n-1) - a(n-2).
1
1, 3, 23, 181, 1425, 11219, 88327, 695397, 5474849, 43103395, 339352311, 2671715093, 21034368433, 165603232371, 1303791490535, 10264728691909, 80814038044737, 636247575665987, 5009166567283159, 39437084962599285, 310487513133511121, 2444463020105489683
OFFSET
0,2
COMMENTS
A105426 extended backwards.
FORMULA
G.f.: (1-5*x)/(1-8*x+x^2). - Philippe Deléham, Mar 28 2009
a(n) = A001090(n+1)-5*A001090(n). - R. J. Mathar, Mar 29 2009
a(n) = (((4-sqrt(15))^n*(1+sqrt(15))+(-1+sqrt(15))*(4+sqrt(15))^n))/(2*sqrt(15)). - Colin Barker, Oct 12 2015
MATHEMATICA
LinearRecurrence[{8, -1}, {1, 3}, 25] (* Vincenzo Librandi, Oct 12 2015 *)
PROG
(PARI) Vec((1-5*x)/(1-8*x+x^2) + O(x^40)) \\ Colin Barker, Oct 12 2015
(Magma) I:=[1, 3]; [n le 2 select I[n] else 8*Self(n-1)-Self(n-2): n in [1..30]]; // Vincenzo Librandi, Oct 12 2015
CROSSREFS
Sequence in context: A110065 A002816 A320265 * A074579 A060880 A331718
KEYWORD
nonn,easy
AUTHOR
N. J. A. Sloane, Mar 28 2009
EXTENSIONS
More terms from Philippe Deléham and R. J. Mathar, Mar 28 2009
STATUS
approved