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A189748 a(1)=5,  a(2)=4, a(n)=5*a(n-1) + 4*a(n-2) 12
5, 4, 40, 216, 1240, 7064, 40280, 229656, 1309400, 7465624, 42565720, 242691096, 1383718360, 7889356184, 44981654360, 256465696536, 1462255100120, 8337138286744, 47534711834200, 271022112317976, 1545249408926680, 8810335493905304, 50232675105233240 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,1

LINKS

Vincenzo Librandi, Table of n, a(n) for n = 1..100

Index entries for linear recurrences with constant coefficients, signature (5, 4).

FORMULA

a(n) = 5/2*((5/2-1/2*sqrt(41))^(n-1)+(5/2+1/2*sqrt(41))^(n-1))+17/82*sqrt(41)*((5/2 -1/2*sqrt(41))^(n-1)-(5/2+1/2*sqrt(41))^(n-1)). - Paolo P. Lava, May 24 2011

G.f.: x*(5-21*x)/(1-5*x-4*x^2). - Bruno Berselli, May 24 2011

MATHEMATICA

LinearRecurrence[{5, 4}, {5, 4}, 40]

PROG

(Maxima) a[1]:5$ a[2]:4$ a[n]:=5*a[n-1]+4*a[n-2]$ makelist(a[n], n, 1, 23);  [Bruno Berselli, May 24 2011]

CROSSREFS

Cf. A000045, A000079, A105476, A159612, A080040, A135522, A103435, A189732, A189734, A189735, A189736, A189737, A189738, A189739, A189741, A189742, A189743, A189744, A189745, A189746, A189747, A189749.

Sequence in context: A078811 A093399 A123233 * A304151 A223527 A262421

Adjacent sequences:  A189745 A189746 A189747 * A189749 A189750 A189751

KEYWORD

nonn

AUTHOR

Harvey P. Dale, Apr 26 2011

STATUS

approved

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Last modified April 11 12:38 EDT 2021. Contains 342886 sequences. (Running on oeis4.)