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Search: id:A073390
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| A073390 |
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Third convolution of A002605(n) (generalized (2,2)-Fibonacci), n>=0, with itself. |
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+0
2
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| 1, 8, 48, 240, 1080, 4512, 17856, 67776, 248880, 889600, 3109376, 10664448, 35989248, 119761920, 393676800, 1280157696, 4122985728, 13165099008, 41713192960, 131243970560, 410315433984, 1275348344832
(list; graph; listen)
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OFFSET
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0,2
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FORMULA
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a(n)=sum(b(k)*c(n-k), k=0..n) with b(k) := A002605(k) and c(k) := A073389(k).
a(n)=(2^n)*sum(binomial(n-k+3, 3)*binomial(n-k, k)*(1/2)^k, k=0..floor(n/2)).
a(n)= ((64+37*n+5*n^2)*(n+1)*U(n+1)+4*(11+7*n+n^2)*(n+2)*U(n))/(6^3), with U(n) := A002605(n), n>=0.
G.f.: 1/(1-2*x*(1+x))^4.
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CROSSREFS
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Fourth (m=3) column of triangle A073387, A073389.
Sequence in context: A093199 A087914 A081084 this_sequence A069021 A079763 A079785
Adjacent sequences: A073387 A073388 A073389 this_sequence A073391 A073392 A073393
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KEYWORD
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nonn,easy
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AUTHOR
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Wolfdieter Lang (wolfdieter.lang(AT)physik.uni-karlsruhe.de), Aug 2, 2002
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