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A105625 Row sums of triangle A105623. 0
1, 2, 7, 40, 324, 3336, 41192, 590480, 9623944, 175703056, 3552295752, 78802665120, 1903505233064, 49743146641616, 1398474578414632, 42092742475096960, 1350629892258170184, 46025643554111478576 (list; graph; refs; listen; history; text; internal format)
OFFSET

0,2

COMMENTS

A105623 equals the matrix square-root of triangle A105615.

LINKS

Table of n, a(n) for n=0..17.

PROG

(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, sum(k=0, n, R[n+1, k+1])))}

CROSSREFS

Cf. A105615, A105623.

Sequence in context: A308876 A162653 A166904 * A135082 A102317 A031973

Adjacent sequences:  A105622 A105623 A105624 * A105626 A105627 A105628

KEYWORD

nonn

AUTHOR

Paul D. Hanna, Apr 16 2005

STATUS

approved

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Last modified January 25 21:23 EST 2021. Contains 340427 sequences. (Running on oeis4.)