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 A307416 #13 May 03 2019 21:36:59
%S A307416 1,1,1,6,144,13440,4976640,7390494720,44033145569280,
%T A307416 1050540969012756480,100246620373125798297600,
%U A307416 38247242364455762072803737600,58346834889692144013481754807500800,355946631376225773365104516210274756198400
%N A307416 Number of narcissistic group-separable preference profiles.
%H A307416 A. Karpov, <a href="https://doi.org/10.1007/s10726-019-09621-w">On the Number of Group-Separable Preference Profiles</a>, Group Decision and Negotiation, 2019, pp. 1-17.
%F A307416 a(n) = Sum_{k=1..n-1} binomial(n-1, k-1)*2^(2*n*k-2*k^2-n)*a(k)*a(n-k).
%o A307416 (PARI) a(n) = {j=1;if(n>1,j=sum(k=1,n-1,binomial(n-1, k-1)*2^(2*n*k-2*k^2-n)*a(k)*a(n-k)));j;} \\ _Jinyuan Wang_, Apr 08 2019
%K A307416 nonn
%O A307416 0,4
%A A307416 _Alexander Karpov_, Apr 07 2019
%E A307416 More terms from _Jinyuan Wang_, Apr 08 2019