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 A274083 #8 Jun 10 2016 04:46:11
%S A274083 1,6,3150,12612600,192972780000,8046096548490000,
%T A274083 747480957758835300000,135330984231708815550000000,
%U A274083 43401712634861734607093640000000,22953694145310867501311470722000000000,18935469872719334117190133449041218500000000
%N A274083 Number of unrooted labeled trees on 4n+2 nodes with node degree either one or five.
%C A274083 There are no unrooted labeled trees on 4n or 4n+1 or 4n+3 nodes with node degree either one or five.
%H A274083 Math.Stackexchange.com, Marko Riedel et al., <a href="http://math.stackexchange.com/questions/1816933/">Number of labeled trees</a>
%p A274083 seq(binomial(4*n+2, n)*(4*n)!/4!^n, n=0..20);
%t A274083 Table[Binomial[4*n+2, n]*(4*n)!/(4!)^n, {n,0,10}] (* _G. C. Greubel_, Jun 09 2016 *)
%Y A274083 Cf. A274056, A000272, A274081.
%K A274083 nonn
%O A274083 0,2
%A A274083 _Marko Riedel_, Jun 09 2016