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A097789
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a(n)=4a(n-1)+C(n+4,4),n>0, a(0)=1.
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0
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1, 9, 51, 239, 1026, 4230, 17130, 68850, 275895, 1104295, 4418181, 17674089, 70698176, 282795084, 1131183396, 4524737460, 18098954685, 72395824725, 289583306215, 1158333233715, 4633332945486, 18533331794594, 74133327193326
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OFFSET
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0,2
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COMMENTS
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LINKS
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FORMULA
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G.f. : 1/((1-4x)(1-x)^5); a(n)=4^(n + 5)/243-(27n^4+414n^3+2385n^2+6198n+6248)/1944; a(n)=sum{k=0..n, binomial(n+5, k+5)3^k}.
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CROSSREFS
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KEYWORD
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easy,nonn
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AUTHOR
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STATUS
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approved
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