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A122887
An upper diagonal of table A122888.
2
1, 10, 118, 1656, 27326, 520626, 11271436, 273613032, 7365210840, 217823497200, 7022714928604, 245186433880584, 9217032342988575, 371216529334562246, 15948164256621353088, 728062466187371268960, 35197679178007576031784
OFFSET
4,2
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
Sequence in context: A307695 A218501 A293987 * A284331 A145510 A160601
KEYWORD
nonn
AUTHOR
Paul D. Hanna, Sep 18 2006
STATUS
approved