A122887 An upper diagonal of table A122888.

1, 10, 118, 1656, 27326, 520626, 11271436, 273613032, 7365210840, 217823497200, 7022714928604, 245186433880584, 9217032342988575, 371216529334562246, 15948164256621353088, 728062466187371268960, 35197679178007576031784

Offset: 4

Author

Paul D. Hanna, Sep 18 2006

Keywords

• nonn

Crossrefs

Cf. A122888; A122892.

Programs

PARI

{a(n)=local(F=x+x^2, G=x+x*O(x^(n+1))); if(n<3, 0, for(i=1, n-2, G=subst(F, x, G)); return(polcoeff(G, n+0, x)))}