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

4,2

Links

Table of n, a(n) for n=4..20.

Prog

(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)))}

Crossrefs

Cf. A122888; A122892.

Sequence in context: A307695 A218501 A293987 * A284331 A145510 A160601

Adjacent sequences: A122884 A122885 A122886 * A122888 A122889 A122890

Keyword

nonn

Author

Paul D. Hanna, Sep 18 2006

Status

approved