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 A115245 #12 Sep 08 2019 12:19:42
%S A115245 3,12,93,6654,43053375,1853020231905216,
%T A115245 3433683820292514337678080994497,
%U A115245 11790184577738583171520872861415952349498504106613519190091458
%N A115245 Partial sums of A011764.
%H A115245 Seiichi Manyama, <a href="/A115245/b115245.txt">Table of n, a(n) for n = 0..11</a>
%t A115245 Accumulate[3^(2^Range[0,10])] (* _Harvey P. Dale_, Oct 14 2012 *)
%o A115245 (PARI) {a(n) = sum(k=0, n, 3^2^k)} \\ _Seiichi Manyama_, Sep 08 2019
%Y A115245 Cf. A011764, A060803.
%K A115245 nonn
%O A115245 0,1
%A A115245 _Roger L. Bagula_, Jun 07 2008