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Search: id:A105630
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| 0, 1, 3, 17, 135, 1353, 16251, 226857, 3605775, 64288209, 1270969971, 27603549057, 653517822615, 16755529944729, 462601460800491, 13685474246611737, 431948067953729055, 14489465807596684449, 514794897939436455651
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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, L[n+1, 1]/2))}
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CROSSREFS
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Cf. A105629, A105623, A105615.
Sequence in context: A163684 A093986 A055214 this_sequence A006290 A060003 A025167
Adjacent sequences: A105627 A105628 A105629 this_sequence A105631 A105632 A105633
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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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