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Search: id:A105631
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| 0, 1, 5, 27, 195, 1833, 21125, 286451, 4453859, 78031153, 1520668645, 32631020011, 764640901539, 19431070911513, 532315915981605, 15640217893829891, 490640673319698179, 16368499360721508833, 578693283962999831365
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OFFSET
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0,3
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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(L, M=matrix(n+1, n+1, 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); L=sum(i=1, #M, (-1)^(i-1)*(M-M^0)^i/i); return(if(n<0, 0, sum(k=0, n, L[n+1, k+1])/2))}
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CROSSREFS
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Cf. A105629, A105623, A105615.
Sequence in context: A091101 A023811 A126119 this_sequence A167019 A135627 A002401
Adjacent sequences: A105628 A105629 A105630 this_sequence A105632 A105633 A105634
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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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