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 A323613 #17 Jan 21 2019 05:55:31
%S A323613 1,1,2,8,27,105,492,2584,14893,93625,637342,4663856,36455959,
%T A323613 302825585,2661650680,24662914640,240141823417,2450053360913,
%U A323613 26125165902810,290487741343352,3361177509359859,40396577112990745,503447944487902244,6496090993661295784,86660903426459105701
%N A323613 Antidiagonal sums of A323182.
%H A323613 Seiichi Manyama, <a href="/A323613/b323613.txt">Table of n, a(n) for n = 0..532</a>
%H A323613 <a href="/index/Ch#Cheby">Index entries for sequences related to Chebyshev polynomials.</a>
%e A323613 a(1) = 0 + 1 = 1.
%e A323613 a(2) = -1 + 2 + 1 = 2.
%e A323613 a(3) = 0 + 3 + 4 + 1 = 8.
%t A323613 Table[Sum[ChebyshevU[k, n - k], {k, 0, n}], {n, 0, 30}] (* _Vaclav Kotesovec_, Jan 20 2019 *)
%o A323613 (PARI) {a(n) = sum(k=0, n, polchebyshev(k, 2, n-k))}
%Y A323613 Cf. A101125, A323182.
%K A323613 nonn
%O A323613 0,3
%A A323613 _Seiichi Manyama_, Jan 20 2019