A105624 Column 2 of triangle A105623.

1, 3, 19, 167, 1831, 23843, 358339, 6097607, 115840951, 2430329603, 55812650419, 1392737182247, 37528377195271, 1086086115808163, 33600297897404899, 1106632150406054087, 38659524289511283991, 1427864216163041265923

Offset: 0

Author

Paul D. Hanna, Apr 16 2005

Keywords

• nonn

Comments

A105623 equals the matrix square-root of triangle A105615.

Crossrefs

Cf. A105615, A105623.

Programs

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,R[n+3,3]))}