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Search: id:A087946
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A087946 Expansion of (1-3x+x^2)/((1-2x)(1-4x+x^2)). +0
2
1, 3, 10, 35, 126, 461, 1702, 6315, 23494, 87533, 326382, 1217483, 4542526, 16950573, 63255670, 236063915, 880983606, 3287837741, 12270301822, 45793238475, 170902389934, 637815796973, 2380359749382, 8883621103403 (list; graph; listen)
OFFSET

0,2

COMMENT

Binomial transform of A057960. a(n)=A087944(n+1)/2.

FORMULA

a(0)=1, a(3)=4, a(2)=10, a(n)=6a(n-1)-9a(n-2)+2a(n-3), n>2; a(n)=2^n/3+(2+sqrt(3))(2+sqrt(3))^n/6+(2-sqrt(3))(2-sqrt(3))^n/6.

CROSSREFS

Sequence in context: A026026 A047037 A134391 this_sequence A122068 A099908 A167403

Adjacent sequences: A087943 A087944 A087945 this_sequence A087947 A087948 A087949

KEYWORD

easy,nonn

AUTHOR

Paul Barry (pbarry(AT)wit.ie), Sep 16 2003

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Last modified November 29 12:46 EST 2009. Contains 167659 sequences.


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