0,2
A105626 equals the cube of the matrix square-root of triangle A105615.
Table of n, a(n) for n=0..16.
(PARI) {a(n)=local(R, M=matrix(n+2, n+2, 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)))))^-3); 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+2, 2]))}
Cf. A105615, A105626.
Sequence in context: A261834 A226740 A244509 * A051578 A052639 A248744
Adjacent sequences: A105624 A105625 A105626 * A105628 A105629 A105630
nonn
Paul D. Hanna, Apr 16 2005
approved
