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%I M4538 N1926 #19 Feb 09 2016 07:39:18
%S 8,52,288,1424,6648,29700,128800,545600,2269672,9303140,37672216,
%T 150998016,599988696,2366216164,9270987656,36116062832,139978757920,
%U 540069059028,2075217121688,7944690769952,30313624200640,115312027433188,437420730644304,1655047867097280,6247339311097296,23530440547115428,88447214709073696,331832490378209152,1242766581420901656,4646714574562484628,17347357264162110368,64668460220964604944,240747014238189337840,895102104022837748484,3323982608759454833032,12329573838525875316560,45684294664598118867184,169098457957523787786644
%N Series-parallel numbers.
%D J. Riordan, An Introduction to Combinatorial Analysis, Wiley, 1958, p. 142.
%D N. J. A. Sloane, A Handbook of Integer Sequences, Academic Press, 1973 (includes this sequence).
%D N. J. A. Sloane and Simon Plouffe, The Encyclopedia of Integer Sequences, Academic Press, 1995 (includes this sequence).
%F G.f.: 4(2+S)(1+S)/(1-S)^5, where S = g.f. for A000084. - _Sean A. Irvine_, Nov 14 2010
%t n = 38; s = 1/(1 - x) + O[x]^(n + 1); Do[s = s/(1 - x^k)^Coefficient[s, x^k] + O[x]^(n + 1), {k, 2, n}] ; S = s - 1; CoefficientList[4 (2 + S) (1 + S)/(1 - S)^5 + O[x]^n, x] (* _Jean-François Alcover_, Feb 09 2016 *)
%K nonn
%O 3,1
%A _N. J. A. Sloane_
%E More terms from _Sean A. Irvine_, Nov 14 2010
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