OFFSET
0,4
LINKS
Alois P. Heinz, Table of n, a(n) for n = 0..100
MAPLE
A:= proc(n) option remember; local T; if n=0 then 1 else T:= A(n-1); unapply(convert(series(1+ x*T(x*T(x*T(x))), x, n+1), polynom), x) fi end: a:= n-> coeff(A(n)(x), x, n): seq(a(n), n=0..21); # Alois P. Heinz, Aug 23 2008
MATHEMATICA
A[n_] := A[n] = Module[{T}, If[n == 0, 1, T[y_] = A[n-1][y]; Normal[Series[1+x*T[x*T[x*T[x]]], {x, 0, n+1}]] /. x -> #]&]; a[n_] := Coefficient[A[n][x], x, n]; Table [a[n], {n, 0, 24}] (* Jean-François Alcover, Feb 14 2014, after Alois P. Heinz *)
CROSSREFS
KEYWORD
nonn
AUTHOR
Paul D. Hanna, Sep 16 2003
STATUS
approved