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A155119 a(n)=5*a(n-1)+5*a(n-2), n>2 ; a(0)=1, a(1)=4, a(2)=24 . 1
1, 4, 24, 140, 820, 4800, 28100, 164500, 963000, 5637500, 33002500, 193200000, 1131012500, 6621062500, 38760375000, 226907187500, 1328337812500, 7776225000000, 45522814062500, 266495195312500, 1540090046875000 (list; graph; refs; listen; history; text; internal format)
OFFSET

0,2

LINKS

Table of n, a(n) for n=0..20.

FORMULA

G.f.: (1-x-x^2)/(1-5*x-5*x^2) .

a(n)=(14/15)*sqrt(5)*{[(5/2)+(3/2)*sqrt(5)]^(n-1)-[(5/2)-(3/2)*sqrt(5)]^(n-1)}+2*{[(5/2)+(3/2)*sqrt(5)]^(n-1)+[(5/2)-(3/2)*sqrt(5)]^(n-1)}+(1/5)*[C(2*n,n) mod 2], with n>=0 [From Paolo P. Lava, Jan 26 2009]

CROSSREFS

Sequence in context: A204199 A262376 A005319 * A114169 A121102 A067411

Adjacent sequences:  A155116 A155117 A155118 * A155120 A155121 A155122

KEYWORD

nonn

AUTHOR

Philippe Deléham, Jan 20 2009

STATUS

approved

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Last modified November 18 19:06 EST 2017. Contains 294894 sequences.