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A113726
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A Jacobsthal convolution.
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1
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1, 0, 1, 4, 5, 8, 25, 44, 77, 176, 353, 660, 1365, 2776, 5417, 10876, 21981, 43648, 87153, 175076, 349669, 698280, 1398585, 2797260, 5590381, 11184720, 22373761, 44735284, 89474165, 178969208, 357910345, 715807004, 1431683837, 2863325216
(list; graph; refs; listen; history; internal format)
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OFFSET
| 0,4
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COMMENTS
| Convolution of A001045(n+1) and A001607(n+1).
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LINKS
| Index to sequences with linear recurrences with constant coefficients, signature (0,1,4,4).
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FORMULA
| G.f.: 1/((1-x-2x^2)(1+x+2x^2)); a(n)=a(n-2)+4a(n-3)+4a(n-4); a(n)=sum{k=0..floor(n/2), C(n-k, k)2^k*(1+(-1)^(n-k))/2}.
a(n) = 2^n/3 +(-1)^n/6+A001607(n+1)/2. - R. J. Mathar, Aug 23 2011
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CROSSREFS
| Cf. A094686, A089977.
Sequence in context: A171938 A072808 A104884 * A140315 A055497 A194419
Adjacent sequences: A113723 A113724 A113725 * A113727 A113728 A113729
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KEYWORD
| easy,nonn
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AUTHOR
| Paul Barry (pbarry(AT)wit.ie), Nov 08 2005
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