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%I #13 Mar 30 2015 09:42:22
%S 1,1,1,2,2,7,16,67,88,617,2626,18176,6949,423271,2172172,19151162,
%T 58438907,899510224,7656246634,1236339998,460251204914,6682341795214,
%U 55431849118769,58399157390146,2845938531282919,54648005951674444,12207653488921678
%N Numerators of coefficients of expansion of exp( Sum_{k=0..oo} x^(2^k)/2^k ) in powers of x.
%H Hiroaki Yamanouchi, <a href="/A256400/b256400.txt">Table of n, a(n) for n = 0..100</a>
%H Koda, Tatsuhiko; Sato, Masaki; Takegahara, Yugen; <a href="http://dx.doi.org/10.1142/S0219498815500528">2-adic properties for the numbers of involutions in the alternating groups</a>, J. Algebra Appl. 14 (2015), no. 4, 1550052 (21 pages). See Lemma 2.1.
%Y For denominators see A049606. Cf. A256401/A256402.
%K nonn,frac
%O 0,4
%A _N. J. A. Sloane_, Mar 29 2015
%E a(18)-a(26) from _Hiroaki Yamanouchi_, Mar 30 2015