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A015564
Expansion of x/(1 - 7*x - 6*x^2).
4
0, 1, 7, 55, 427, 3319, 25795, 200479, 1558123, 12109735, 94116883, 731476591, 5685037435, 44184121591, 343399075747, 2668898259775, 20742682272907, 161212165468999, 1252941251920435, 9737861756257039, 75682679805321883
OFFSET
0,3
COMMENTS
Pisano period lengths: 1, 1, 1, 1, 12, 1, 4, 2, 3, 12, 15, 1, 168, 4, 12, 4, 288, 3, 18, 12, ... - R. J. Mathar, Aug 10 2012
LINKS
Lucyna Trojnar-Spelina and Iwona Włoch, On Generalized Pell and Pell-Lucas Numbers, Iranian Journal of Science and Technology, Transactions A: Science (2019), 1-7.
FORMULA
a(n) = 7*a(n-1) + 6*a(n-2).
MATHEMATICA
LinearRecurrence[{7, 6}, {0, 1}, 30] (* Vincenzo Librandi, Nov 14 2012 *)
PROG
(Sage) [lucas_number1(n, 7, -6) for n in range(0, 21)] # Zerinvary Lajos, Apr 24 2009
(Magma) [n le 2 select n-1 else 7*Self(n-1) + 6*Self(n-2): n in [1..30]]; // Vincenzo Librandi, Nov 14 2012
(PARI) x='x+O('x^30); concat([0], Vec(x/(1-7*x-6*x^2))) \\ G. C. Greubel, Dec 30 2017
CROSSREFS
Sequence in context: A198689 A320091 A172743 * A070997 A370177 A122372
KEYWORD
nonn,easy
STATUS
approved