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Search: id:A144631
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| 4, 12, 880, 46900, 1615824, 45094896, 1115345088, 25519125060, 553014576400, 11514200107696, 232490008680384, 4581732884262352, 88532684825838400, 1683073282734360000, 31561148509363526400, 584964180982546208100
(list; graph; listen)
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OFFSET
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2,1
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LINKS
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Klaus Brockhaus, Table of n, a(n) for n=2..100
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MAPLE
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invH := proc(n, i, j) (-1)^(i+j)*(i+j-1)*binomial(n+i-1, n-j)*binomial(n+j-1, n-i)* (binomial(i+j-2, i-1))^2 ; end: A144630 := proc(n, k) local T, i, j ; T := 0 ; for i from n-k+1 to n do for j from n-k+1 to n do T := T+invH(n, i, j) ; od; od; RETURN(T) ; end: A144631 := proc(n) A144630(n+1, 2) ; end: for n from 1 to 20 do printf("%a, ", A144631(n)) : od: [From R. J. Mathar (mathar(AT)strw.leidenuniv.nl), Jan 21 2009]
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PROGRAM
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(MAGMA) [ [ &+[I[i][j]: i, j in [k..n] ]: k in [n..1 by -1] ][2] where I:=H^-1 where H:=Matrix(Rationals(), n, n, [ < i, j, 1/(i+j-1) >: i, j in [1..n] ] ): n in [2..17] ]; [From Klaus Brockhaus (klaus-brockhaus(AT)t-online.de), Jan 22 2009]
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CROSSREFS
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Sequence in context: A009506 A085116 A104129 this_sequence A009516 A146210 A024248
Adjacent sequences: A144628 A144629 A144630 this_sequence A144632 A144633 A144634
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KEYWORD
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nonn
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AUTHOR
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Daniel McLaury and Ben Golub, Jan 20 2009
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EXTENSIONS
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More terms from R. J. Mathar (mathar(AT)strw.leidenuniv.nl) and Klaus Brockhaus (klaus-brockhaus(AT)t-online.de), Jan 21 2009
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