%I M1777 #16 Nov 07 2017 18:39:07
%S 1,1,2,7,27,118,537,2570,12587,63173,322385,1669144,8742999,46253727,
%T 246771340,1326236480,7173280391,39017312543,213287030596,
%U 1171140510636,6456473371424,35723687996130,198311302682834,1104189489401230
%N Number of blobs with 2n+1 edges.
%D N. J. A. Sloane and Simon Plouffe, The Encyclopedia of Integer Sequences, Academic Press, 1995 (includes this sequence).
%H R. C. Read, <a href="http://dx.doi.org/10.1007/BF02188172">On the enumeration of a class of plane multigraphs</a>, Aequat. Math. 31 (1986) no 1, 47-63.
%o (PARI) { s =y ; for(loop=1,18, p = 1 ; forstep(i= 1,2*loop-1,2, sigmai = polcoeff(s,i,y) ; n=0 ; tmp = 0 ; while(i*n <=2*loop-1, ff = 1 ; for(k=1,n, ff *= (-sigmai-k+1)/k ; ) ; tmp += ff*(-y)^(i*n) ; n++ ; ) ; p *= tmp : ) ; b = y-s ; forstep(i=1,2*loop-1,2, b += polcoeff(p,i,y)*y^i ; ) ; print1(polcoeff(b,2*loop-1,y),",") ; s = y ; for(r=0,loop-1, for(i=0,2*loop+1, s += polcoeff(b^(3+2*r),i,y)*y^i ; ) ; ) ; ) ; } \\ _R. J. Mathar_, Apr 24 2006
%K nonn
%O 0,3
%A _N. J. A. Sloane_.
%E More terms from _R. J. Mathar_, Apr 24 2006
%E More terms from _Sean A. Irvine_, Nov 07 2017