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%I #24 Nov 30 2021 03:46:14
%S 0,0,1,3,0,5,7,7,8,8,12,14,14,15,16,18,18,19,21,24,24,26,28,29,26,27,
%T 32,34,35,35,37,36,38,39,40,41,43,46,48,49,47,50,53,55,55,56,58,59,57,
%U 56,61,64,64,66,68,70,70,71,73,75,76,76,76,78,78,79,80,82
%N Log_2 of denominators of coefficients in the e.g.f. a(x) such that a(a(x)) = exp(x) - 1.
%D R. P. Stanley, Enumerative Combinatorics, Cambridge, Vol. 2, 1999; see Problem 5.52.
%e x + (1/4)*x^2 + (1/48)*x^3 + (1/3840)*x^5 - (7/92160)*x^6 + (1/645120)*x^7 + ...
%t T[n_, n_] = 1; T[n_, m_] := T[n, m] = (StirlingS2[n, m]*m!/n! - Sum[T[n, i]*T[i, m], {i, m+1, n-1}])/2; Table[n!*T[n, 1] // Denominator // Log[2, #]&, {n, 0, 29}] (* _Jean-François Alcover_, Mar 03 2014, after A052104 and _Alois P. Heinz_ *)
%Y Cf. A052122, A052104, A052105.
%K nonn,frac,easy
%O 0,4
%A _N. J. A. Sloane_, Jan 23 2000
%E More terms from _Vladeta Jovovic_, Jul 27 2002
%E More terms from _Sean A. Irvine_, Oct 25 2021
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