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 A073588 #21 Jun 19 2021 10:55:21
%S A073588 1,3,23,367,11743,751551,96198527,24626822911,12608933330431,
%T A073588 12911547730361343,26442849751780030463,108309912583291004776447,
%U A073588 887274803882319911128653823,14537110386807929423931864236031
%N A073588 a(n) = a(n-1)*2^n-1 with a(1)=1.
%F A073588 a(n) = ceiling(C*2^(n*(n+1)/2)) where C is a constant, C = 0.3583674393448461337061572297745... In fact, C = Sum_{k>=0} 1/2^(k*(k+1)/2) - 1/2^(k*(k+3)/2) = Sum_{k>=0} 1/2^A000217(k) - Sum_{k>=0} 1/2^A000096(k). - _Benoit Cloitre_, Sep 01 2002
%F A073588 a(n) = ceiling(C*2^(n*(n+1)/2)) where C is a constant, C = 0.3583674393448461337061572297745... - _Benoit Cloitre_, Sep 01 2002
%t A073588 a = 1; Table[a = a*2^n - 1, {n, 14}] (* _Jayanta Basu_, Jul 02 2013 *)
%K A073588 easy,nonn
%O A073588 1,2
%A A073588 _Felice Russo_, Aug 28 2002
%E A073588 Definition corrected by _Georg Fischer_, Jun 19 2021