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 A320859 #22 Sep 08 2022 08:46:23
%S A320859 32,32768,33554432,34359738368,35184372088832,36028797018963968,
%T A320859 36893488147419103232,37778931862957161709568,
%U A320859 302231454903657293676544,38685626227668133590597632,309485009821345068724781056,39614081257132168796771975168,316912650057057350374175801344
%N A320859 Powers of 2 with initial digit 3.
%H A320859 Muniru A Asiru, <a href="/A320859/b320859.txt">Table of n, a(n) for n = 1..410</a>
%H A320859 <a href="/index/Di#divseq">Index to divisibility sequences</a>
%F A320859 a(n) = 2^A172404(n).
%p A320859 select(x->"3"=""||x[1],[2^n$n=0..120])[];
%t A320859 Select[2^Range[0, 100], First[IntegerDigits[#]] == 3 &] (* _G. C. Greubel_, Oct 24 2018 *)
%o A320859 (GAP) Filtered(List([0..120],n->2^n),i->ListOfDigits(i)[1]=3);
%o A320859 (Magma) [2^n: n in [1..100] | Intseq(2^n)[#Intseq(2^n)] eq 3]; // _G. C. Greubel_, Oct 24 2018
%o A320859 (PARI) lista(nn) = {for(n=1, nn, x = 2^n; if (digits(x=2^n)[1] == 3, print1(x, ", ")););} \\ _Michel Marcus_, Oct 25 2018
%Y A320859 Cf. A000079 (Powers of 2), A008952 (leading digit of 2^n).
%Y A320859 Powers of 2 with initial digit k, (k = 1..4): A067488, A067480, this sequence, A320860.
%Y A320859 Cf. A172404.
%K A320859 base,nonn
%O A320859 1,1
%A A320859 _Muniru A Asiru_, Oct 22 2018