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Search: id:A105624
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| 1, 3, 19, 167, 1831, 23843, 358339, 6097607, 115840951, 2430329603, 55812650419, 1392737182247, 37528377195271, 1086086115808163, 33600297897404899, 1106632150406054087, 38659524289511283991, 1427864216163041265923
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OFFSET
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0,2
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COMMENT
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A105623 equals the matrix square-root of triangle A105615.
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PROGRAM
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(PARI) {a(n)=local(R, M=matrix(n+3, n+3, m, j, if(m>=j, if(m==j, 1, if(m==j+1, -2*j, polcoeff(1/sum(i=0, m-j, (2*i)!/i!/2^i*x^i)+O(x^m), m-j)))))^-1); R=(M+M^0)/2; for(i=1, floor(2*log(n+2)), R=(R+M*R^(-1))/2); return(if(n<0, 0, R[n+3, 3]))}
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CROSSREFS
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Cf. A105615, A105623.
Sequence in context: A054765 A057719 A136474 this_sequence A080835 A080836 A059280
Adjacent sequences: A105621 A105622 A105623 this_sequence A105625 A105626 A105627
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KEYWORD
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nonn
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AUTHOR
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Paul D. Hanna (pauldhanna(AT)juno.com), Apr 16 2005
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