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+4))), M, N, P); M=matrix(n+4, n+4, r, c, F=x; for(i=1, r+c-2, F=subst(F, x, CAT)); polcoeff(F, c)); N=matrix(n+3, n+3, r, c, M[r, c]); P=matrix(n+3, n+3, r, c, M[r+1, c]); (P~*N~^-1)[n+3, 3]}

Cf. A158835, A158836, A158837, A158839, A158840.

Sequence in context: A087918 A088926 A120972 this_sequence A107716 A032033 A099121

Adjacent sequences: A158835 A158836 A158837 this_sequence A158839 A158840 A158841

nonn

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