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Search: id:A073391
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| A073391 |
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Fourth convolution of A002605(n) (generalized (2,2)-Fibonacci), n>=0, with itself. |
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+0
2
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| 1, 10, 70, 400, 2020, 9352, 40600, 167680, 665440, 2555840, 9551936, 34880000, 124853120, 439228160, 1521839360, 5202292736, 17571249920, 58712184320, 194280061440, 637228462080, 2073332481024, 6696470231040
(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) := A073390(k).
a(n)=(2^n)*sum(binomial(n-k+4, 4)*binomial(n-k, k)*(1/2)^k, k=0..floor(n/2)).
a(n)= (2*(419+326*n+79*n^2+6*n^3)*(n+1)*U(n+1)+(458+421*n+112*n^2+9*n^3)*(n+2)*U(n))/(2^5*3^4), with U(n) := A002605(n), n>=0.
G.f.: 1/(1-2*x*(1+x))^5.
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CROSSREFS
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Fifth (m=4) column of triangle A073387, A073390.
Sequence in context: A090084 A025221 A005567 this_sequence A002802 A101029 A122892
Adjacent sequences: A073388 A073389 A073390 this_sequence A073392 A073393 A073394
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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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