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 A027305 #13 Oct 27 2019 11:36:24
%S A027305 1,3,5,13,24,58,111,257,500,1126,2210,4882,9632,20980,41531,89497,
%T A027305 177564,379438,754014,1600406,3184016,6720748,13382710,28117498,
%U A027305 56026984,117254268,233765636,487589572,972504704,2022568168
%N A027305 a(n) = Sum_{k=0..floor((n+1)/2)} (k+1) * A008315(n, k).
%F A027305 a(2n) = A065982(n+1)/2 = (n+2)*binomial(2n+2, n+1)/2 - 4^n.
%Y A027305 Cf. A065982.
%K A027305 nonn
%O A027305 0,2
%A A027305 _Clark Kimberling_