A105625 Row sums of triangle A105623.

1, 2, 7, 40, 324, 3336, 41192, 590480, 9623944, 175703056, 3552295752, 78802665120, 1903505233064, 49743146641616, 1398474578414632, 42092742475096960, 1350629892258170184, 46025643554111478576

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: A162653 A346220 A166904 * A367255 A135082 A102317

Adjacent sequences: A105622 A105623 A105624 * A105626 A105627 A105628

Keyword

nonn

Author

Paul D. Hanna, Apr 16 2005

Status

approved