



1, 6, 84, 1638, 38976, 1068480, 32716992, 1098069504, 39896236800, 1555603999488, 64678765165056, 2853714891138048, 133101200708356608, 6542154022577467392, 337978986519657627648, 18310837206705702672384
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OFFSET

0,2


LINKS

Vaclav Kotesovec, Table of n, a(n) for n = 0..350


FORMULA

G.f.: A(x) = 1 + 6x*R(x,6)^2, where R(x,6) = 1 + 7*x*R(x,7)^2, R(x,7) = 1 + 8*x*R(x,8)^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.
a(n) ~ 128*n^5*A128318(n)/3645.  Vaclav Kotesovec, Mar 19 2016


PROG

(PARI) {a(n)=local(A=1+(n+6)*x); for(j=0, n, A=1+(n+6j)*x*A^2 +x*O(x^n)); polcoeff(A, n)}


CROSSREFS

Cf. A128570 (triangle), other rows: A128318, A128571, A128572, A128573, A128574, A128576; A128577 (square of row 0), A128578 (main diagonal), A128579 (antidiagonal sums).
Sequence in context: A163947 A306244 A277304 * A322518 A014062 A147626
Adjacent sequences: A128572 A128573 A128574 * A128576 A128577 A128578


KEYWORD

nonn


AUTHOR

Paul D. Hanna, Mar 11 2007


STATUS

approved



