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A076148 Let b(1)=x, b(2)=y, k*b(k)=(2k-1)*b(k-1) + 3(k+1)*b(k-2); then b(n)=a(n)*x+c(n)/3*y. 0
1, 0, 4, 7, 27, 74, 230, 681, 2053, 6148, 18456, 55355, 166079, 498222, 1494682, 4484029, 13452105, 40356296, 121068908, 363206703, 1089620131, 3268860370, 9806581134, 29419743377, 88259230157, 264777690444, 794333071360 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,3

LINKS

Table of n, a(n) for n=1..27.

FORMULA

a(1)=1; a(n+1) = 3*a(n)+(-1)^n*(n+2); a(n)=floor((5/16)*3^(n-1)-(-1)^n*n/4+1/2)

CROSSREFS

Sequence in context: A269744 A303844 A197789 * A203570 A146085 A061668

Adjacent sequences:  A076145 A076146 A076147 * A076149 A076150 A076151

KEYWORD

nonn

AUTHOR

Benoit Cloitre, Nov 02 2002

STATUS

approved

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Last modified July 31 06:15 EDT 2021. Contains 346369 sequences. (Running on oeis4.)