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A180226 a(n) = 4*a(n-1) + 10*a(n-2), with a(1)=0 and a(2)=1. 11
0, 1, 4, 26, 144, 836, 4784, 27496, 157824, 906256, 5203264, 29875616, 171535104, 984896576, 5654937344, 32468715136, 186424233984, 1070384087296, 6145778689024, 35286955629056, 202605609406464, 1163291993916416, 6679224069730304, 38349816218085376 (list; graph; refs; listen; history; text; internal format)
OFFSET
1,3
LINKS
FORMULA
a(n) = ((2+sqrt(14))^(n-1) - (2-sqrt(14))^(n-1))/(2*sqrt(14)). - Rolf Pleisch, May 14 2011
G.f.: x^2/(1-4*x-10*x^2).
MATHEMATICA
Join[{a=0, b=1}, Table[c=4*b+10*a; a=b; b=c, {n, 100}]]
LinearRecurrence[{4, 10}, {0, 1}, 30] (* G. C. Greubel, Jan 16 2018 *)
PROG
(PARI) x='x+O('x^30); concat([0], Vec(x^2/(1-4*x-10*x^2))) \\ G. C. Greubel, Jan 16 2018
(Magma) I:=[0, 1]; [n le 2 select I[n] else 4*Self(n-1) + 10*Self(n-2): n in [1..30]]; // G. C. Greubel, Jan 16 2018
CROSSREFS
Sequence in context: A197964 A100236 A229278 * A325587 A223627 A144068
KEYWORD
nonn,easy
AUTHOR
STATUS
approved

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Last modified March 1 17:48 EST 2024. Contains 370442 sequences. (Running on oeis4.)