0,2

Triangle A158835 transforms diagonals in the array A158825 of coefficients of successive iterations of x*C(x) where C(x) is the Catalan function (A000108).

(PARI) {a(n)=local(F=x, CAT=serreverse(x-x^2+x*O(x^(n+2))), M, N, P); M=matrix(n+2, n+2, r, c, F=x; for(i=1, r+c-2, F=subst(F, x, CAT)); polcoeff(F, c)); N=matrix(n+1, n+1, r, c, M[r, c]); P=matrix(n+1, n+1, r, c, M[r+1, c]); sum(k=0, n, (P~*N~^-1)[n+1, k+1])}

Cf. A158835, A158836, A158837, A158838, A158839.

Sequence in context: A159315 A109172 A131682 this_sequence A038052 A066383 A011802

Adjacent sequences: A158837 A158838 A158839 this_sequence A158841 A158842 A158843

nonn

Paul D. Hanna (pauldhanna(AT)juno.com), Mar 28 2009