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 A362886 #4 May 20 2023 16:08:55
%S A362886 1,1,4,12,37,123,440,1686,6901,30085,139212,681336,3515397,19064135,
%T A362886 108370384,644142962,3994439189,25789465377,173033812804,
%U A362886 1204425693988,8683782562597,64757730613875,498827437211176,3964154812486062,32463601480302005,273670283527555869
%N A362886 Antidiagonal sums of A362885.
%F A362886 a(n) = Sum_{k=0..n} (1 + 2*(n - k))*k^(n-k).
%t A362886 Join[{1},Table[Sum[(1+2(n-k))k^(n-k),{k,0,n}],{n,25}]]
%Y A362886 Cf. A362885.
%K A362886 nonn
%O A362886 0,3
%A A362886 _Stefano Spezia_, May 08 2023