login
A128577
Self-convolution of A128318.
11
1, 2, 9, 64, 624, 7736, 116416, 2060808, 41952600, 965497440, 24786054816, 702201877920, 21761251764672, 732269872931712, 26589359234860560, 1036241806935453696, 43142510740036313088, 1911022260200150482944, 89737455913330610995200, 4452805047268938247981056, 232806644343118618035904512, 12791828071344703747110764544, 736928909474399720669590216704, 44416721474748725213260027514880
OFFSET
0,2
COMMENTS
A128318 equals row 0 of table A128570.
LINKS
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.
a(n) ~ 2*A128318(n). - Vaclav Kotesovec, Mar 19 2016
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)}
for(n=0, 25, print1(a(n), ", "))
CROSSREFS
Cf. A128570 (triangle), rows: A128318, A128571, A128572, A128573, A128574, A128575, A128576; A128578 (main diagonal), A128579 (antidiagonal sums).
Sequence in context: A269770 A269649 A335517 * A052514 A274395 A036776
KEYWORD
nonn
AUTHOR
Paul D. Hanna, Mar 11 2007
STATUS
approved