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A381574
G.f. A(x) satisfies A(x) = 1/(1 - x*A(x*A(x)))^3.
0
1, 3, 15, 118, 1206, 14712, 204385, 3143826, 52580328, 944416084, 18056415144, 365065244238, 7765839784508, 173123253590079, 4031536347783786, 97807655876704029, 2466489368705170539, 64527021089110890192, 1748298996924574135699, 48982266056400514509660
OFFSET
0,2
FORMULA
See A381573.
PROG
(PARI) a(n, k=1) = if(k==0, 0^n, 3*k*sum(j=0, n, binomial(3*n-2*j+3*k, j)/(3*n-2*j+3*k)*a(n-j, j)));
CROSSREFS
Column k=1 of A381573.
Cf. A381570.
Sequence in context: A259843 A136654 A364621 * A145161 A121422 A060639
KEYWORD
nonn,new
AUTHOR
Seiichi Manyama, Feb 28 2025
STATUS
approved