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 A068034 #13 Sep 08 2022 13:31:47
%S A068034 1,1,1,1,1,2,5,10,20,39,79,158,316,632,1262,2522,5042,10082,20164,
%T A068034 40330,80660,161320,322638,645278,1290556,2581112,5162224,10324444,
%U A068034 20648884,41297764,82595524,165191048,330382100,660764200,1321528400
%N A068034 Number of subsets of {1,2,3,...,n} that sum to 0 mod 13.
%F A068034 Empirical G.f.: -(2*x^13-x^10+x^9-x^6+x^4+x^3+x^2+x-1) / ((2*x-1)*(2*x^13-1)). [_Colin Barker_, Dec 22 2012]
%t A068034 Table[Count[Subsets[Range[n]], _?(Divisible[Total[#], 13]&)], {n,20}] (* _Harvey P. Dale_, Feb 14 2012 *)
%Y A068034 13th row of A068009.
%K A068034 nonn
%O A068034 0,6
%A A068034 _Antti Karttunen_, Feb 11 2002