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A155195 a(n)=6*a(n-1)+a(n-2), n>2 ; a(0)=1, a(1)=5, a(2)=30 . 1
1, 5, 30, 185, 1140, 7025, 43290, 266765, 1643880, 10130045, 62424150, 384674945, 2370473820, 14607517865, 90015581010, 554701003925, 3418221604560, 21064030631285, 129802405392270, 799878462984905, 4929073183301700 (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)/(1-6*x-x^2).

a(n)=(3/4)*sqrt(10)*{[3+sqrt(10)]^(n-1)-[3-sqrt(10)]^(n-1)}+(5/2)*{[3+sqrt(10)]^(n-1)+[3-sqrt(10)]^(n-1)}+[C(2*n,n) mod 2], with n>=0 [From Paolo P. Lava, Jan 26 2009]

a(n) = Sum_{k, 0<=k<=n} A155161(n,k)*5^k. - Philippe Deléham, Feb 08 2012

CROSSREFS

Sequence in context: A052934 A136785 A227383 * A147837 A076036 A195257

Adjacent sequences:  A155192 A155193 A155194 * A155196 A155197 A155198

KEYWORD

nonn,easy

AUTHOR

Philippe Deléham, Jan 21 2009

STATUS

approved

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Last modified February 16 21:26 EST 2020. Contains 331975 sequences. (Running on oeis4.)