0,2
A105623 equals the matrix square-root of triangle A105615.
(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]))}
Cf. A105615, A105623.
Sequence in context: A136474 A183069 A201123 * A080835 A080836 A059280
Adjacent sequences: A105621 A105622 A105623 * A105625 A105626 A105627
nonn
Paul D. Hanna (pauldhanna(AT)juno.com), Apr 16 2005
