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Search: id:A097112
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| A097112 |
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Expansion of (1+4x-6x^2-36x^3)/(1-19x^2+90x^4). |
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+0
1
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| 1, 4, 13, 40, 157, 400, 1813, 4000, 20317, 40000, 222853, 400000, 2405677, 4000000, 25651093, 40000000, 270859837, 400000000, 2837738533, 4000000000, 29539646797, 40000000000, 305856821173, 400000000000, 3152711390557
(list; graph; listen)
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OFFSET
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0,2
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FORMULA
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G.f. : 4(1+x)/(1-10x^2)-3/(1-9x^2); a(n)=19a(n-2)-90a(n-4); a(n)=(2+sqrt(10)/5)(sqrt(10))^n+(2-sqrt(10)/5)(-sqrt(10))^n-3^(n+1)(1+(-1)^n)/2; a(n)=sum{k=0..n, binomial(floor(n/2), floor(k/2))3^k }
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CROSSREFS
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Sequence in context: A094628 A034742 A149424 this_sequence A077284 A070428 A052529
Adjacent sequences: A097109 A097110 A097111 this_sequence A097113 A097114 A097115
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KEYWORD
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easy,nonn
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AUTHOR
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Paul Barry (pbarry(AT)wit.ie), Jul 25 2004
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