A105616 Column 1 of triangle A105615.

1, 4, 26, 226, 2426, 30826, 451586, 7489426, 138722426, 2839238026, 63654973826, 1551919194226, 40888965122426, 1157981114051626, 35083865696279426, 1132449247218851026, 38800104353355372026, 1406432065083818193226

Offset: 0

Author

Paul D. Hanna, Apr 16 2005

Keywords

• nonn

Comments

Also equals column 0 of triangle A105623 (offset 1), where A105623 equals the matrix square-root of triangle A105615.

Crossrefs

Cf. A105615, A105623.

Programs

PARI

{a(n)=if(n<0,0,(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) ))))^-1)[n+2,2])}