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 A006898 M2958 #48 Apr 01 2023 11:04:50
%S A006898 1,3,13,95,1337,38619,2310533,283841911,70927591153,35812691480115,
%T A006898 36383765777442685,74185239630793429775,303119284294591169426729,
%U A006898 2479814853198140771706795531,40599509058360322571947638063605
%N A006898 a(n) = Sum_{k=0..n} C(n,k)*2^(k*(k+1)/2).
%C A006898 First differences of A006896.
%D A006898 N. J. A. Sloane and Simon Plouffe, The Encyclopedia of Integer Sequences, Academic Press, 1995 (includes this sequence).
%F A006898 a(n) ~ 2^(n*(n+1)/2). - _Vaclav Kotesovec_, Nov 27 2017
%t A006898 Table[Sum[Binomial[n,k]2^((k(k+1))/2),{k,0,n}],{n,0,20}] (* _Harvey P. Dale_, Apr 01 2023 *)
%o A006898 (PARI) a(n)=sum(k=0,n,binomial(n,k)*2^(k*(k+1)/2)) \\ _Paul D. Hanna_, Apr 10 2009
%Y A006898 Cf. A006896, A006897, A135748.
%K A006898 nonn
%O A006898 0,2
%A A006898 _Colin Mallows_
%E A006898 Formula and more terms from _Vladeta Jovovic_, Sep 20 2003
%E A006898 Edited by _N. J. A. Sloane_, Apr 12 2009 at the suggestion of Vladeta Jovovic