A372537 G.f. A(x) satisfies A(A(A(A(x)))) = x + 4*x^2 + 16*x^3.
0, 1, 1, 1, -15, 81, -159, -1695, 19857, -77775, -372351, 6628545, -24096975, -232640751, 2756221601, 2199811873, -210934282287, 553408050417, 17722961332929, -95716389015423, -1950283855292559, 15527782649242065, 285278599792984545, -3006768595808218911
Offset: 0
Keywords
Examples
A(A(x)) = x + 2*x^2 + 4*x^3 - 24*x^4 + 80*x^5 + 32*x^6 - 2496*x^7 + 14976*x^8 + ...
Links
- Seiichi Manyama, Table of n, a(n) for n = 0..486
Formula
Define the sequence b(n,m) as follows. If n
Let B(x) = A(A(x)).
B(B(x)) = x + 4*x^2 + 16*x^3.
B(x) = F(2*x)/2, where F(x) is the g.f. for A220110.