This is a front-end for the Online Encyclopedia of Integer Sequences, made by Christian Perfect. The idea is to provide OEIS entries in non-ancient HTML, and then to think about how they're presented visually. The source code is on GitHub.
%I A056711 #14 Apr 13 2017 16:49:17 %S A056711 0,0,0,1,2,8,28,100,358,1309,4772,17556,64782,240090,892662,3329942, %T A056711 12456782,46725350,175698056,662193908,2501118956,9465771967, %U A056711 35891640172,136331485336,518702002350,1976588406300,7543137149256,28826327724850,110304963059048 %N A056711 Plug g.f. for A000108 (minus the leading 1), 1/2*(1-(1-4*x)^(1/2))/x - 1, into cycle index for dihedral group D_3. %H A056711 Alois P. Heinz, <a href="/A056711/b056711.txt">Table of n, a(n) for n = 0..1000</a> %F A056711 Cycle index for D_3: 1/6*Z[1]^3+1/2*Z[1]*Z[2]+1/3*Z[3]. %F A056711 O.g.f.: 1/6*A(x)^3 + 1/2*A(x)*A(x^2) + 1/3*A(x^3), with A(x):=1/2*(1-(1-4*x)^(1/2))/x - 1 (see the name). For the cycle index of the dihedral group D_n see A212355 for the Harary-Palmer reference, the formula and a link. - _Wolfdieter Lang_, Jun 02 2012 %Y A056711 Cf. A000108, A058855, A046342. %Y A056711 Column k=3 of A275431. %K A056711 nonn %O A056711 0,5 %A A056711 _N. J. A. Sloane_, Jan 19 2001