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A128577 Self-convolution of A128318. 9
1, 2, 9, 64, 624, 7736, 116416, 2060808, 41952600, 965497440, 24786054816, 702201877920, 21761251764672, 732269872931712, 26589359234860560, 1036241806935453696, 43142510740036313088, 1911022260200150482944 (list; graph; refs; listen; history; internal format)
OFFSET

0,2

COMMENTS

A128318 equals row 0 of table A128570.

FORMULA

G.f.: A(x) = [1 + x*R(x,1)^2]^2, where R(x,1) = 1 + 2*x*R(x,2)^2, R(x,2) = 1 + 3*x*R(x,3)^2, ..., R(x,n) = 1 + (n+1)*x*R(x,n+1)^2, ... and R(x,n) is the g.f. of row n of table A128570.

PROG

(PARI) {a(n)=local(A=1+(n+1)*x); for(j=0, n, A=1+(n+1-j)*x*A^2 +x*O(x^n)); polcoeff(A^2, n)}

CROSSREFS

Cf. A128570 (triangle), rows: A128318, A128571, A128572, A128573, A128574, A128575, A128576; A128578 (main diagonal), A128579 (antidiagonal sums).

Sequence in context: A179199 A036775 A141209 * A052514 A036776 A036777

Adjacent sequences:  A128574 A128575 A128576 * A128578 A128579 A128580

KEYWORD

nonn

AUTHOR

Paul D. Hanna (pauldhanna(AT)juno.com), Mar 11 2007

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Last modified February 16 18:43 EST 2012. Contains 205939 sequences.