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Search: id:A006645
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| 0, 0, 1, 4, 14, 44, 131, 376, 1052, 2888, 7813, 20892, 55338, 145428, 379655, 985520, 2545720, 6547792, 16777993, 42847988, 109099078, 277040572, 701794187, 1773851304, 4474555476, 11266301976
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OFFSET
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0,4
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FORMULA
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a(n)= sum(b(k)*b(n-k), k=0..n) with b(k) := A000129(k).
a(n)= sum(2^(n-2)*(n-k-1)*binomial(n-2-k, k)*(1/4)^k, k=0..floor((n-2)/2)), n>=2.
a(n)= ((n-1)*P(n)+n*P(n-1))/4, P(n)=A000129(n). G.f.: (x/(1-2*x-x^2))^2 - Wolfdieter Lang (wolfdieter.lang(AT)physik.uni-karlsruhe.de), Apr 11 2000
a(n)=F'(n, 2), the derivative of the n-th Fibonacci polynomial evaluated at x=2. - T. D. Noe (noe(AT)sspectra.com), Jan 19 2006
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CROSSREFS
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a(n)= A054456(n-1, 1), n>=1 (second column of triangle), A054457.
Sequence in context: A007466 A062109 A118042 this_sequence A094309 A000300 A005323
Adjacent sequences: A006642 A006643 A006644 this_sequence A006646 A006647 A006648
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KEYWORD
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nonn
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AUTHOR
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njas
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EXTENSIONS
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Sum formulae and cross-references added.- Wolfdieter Lang (wolfdieter.lang(AT)physik.uni-karlsruhe.de), Aug 07 2002
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