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A097111
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Expansion of (1+3x-2x^2-12x^3)/(1-9x^2+20x^4).
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0
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1, 3, 7, 15, 43, 75, 247, 375, 1363, 1875, 7327, 9375, 38683, 46875, 201607, 234375, 1040803, 1171875, 5335087, 5859375, 27199723, 29296875, 138095767, 146484375, 698867443, 732421875, 3527891647, 3662109375, 17773675963, 18310546875
(list; graph; refs; listen; history; internal format)
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OFFSET
| 0,2
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FORMULA
| G.f. : 3(1+x)/(1-5x^2)-2/(1-4x^2); a(n)=9a(n-2)-20a(n-4); a(n)=(3/2+3sqrt(5)/10)(sqrt(5))^n+(3/2-3sqrt(5)/10)(-sqrt(5))^n-2^(n+1)(1+(-1)^n)/2; a(n)=sum{k=0..n, binomial(floor(n/2), floor(k/2))2^k }
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CROSSREFS
| Sequence in context: A146033 A147188 A050565 * A151401 A080567 A146448
Adjacent sequences: A097108 A097109 A097110 * A097112 A097113 A097114
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KEYWORD
| easy,nonn
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AUTHOR
| Paul Barry (pbarry(AT)wit.ie), Jul 25 2004
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