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 A064188 #7 Jun 19 2023 08:04:31
%S A064188 1,1,3,4,8,12,18,27,40,58,83,118,195,242,-1387,-338,75876,44491,
%T A064188 -3099115,-2028539,129829195,91749709,-5687984421,-4236497556,
%U A064188 263653557716,204087552038,-12979768392096,-10348229609729,679042377362009,554161706136054,-37712174126966326
%N A064188 a(n) = Sum_{k=0..floor(n/2)} binomial(n - k*(k-1)/2, k).
%t A064188 Table[ Sum[ Binomial[ n - i*(i - 1)/2, i ], {i, 0, Floor[ n/2 ] } ], {n, 0, 30} ]
%o A064188 (PARI) a(n) = sum(k=0, n\2, binomial(n - k*(k-1)/2, k)); \\ _Michel Marcus_, Jun 19 2023
%Y A064188 Cf. A063978.
%K A064188 sign
%O A064188 0,3
%A A064188 Helmut Schnitzspan (HSchnitzspan(AT)gmx.de), Sep 05 2001
%E A064188 More terms from _Robert G. Wilson v_, Sep 06 2001
%E A064188 Missing a(0)=1 inserted by _Sean A. Irvine_, Jun 18 2023