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 A114645 #17 Dec 25 2022 14:02:40
%S A114645 137,153,163,127,255,511,102,320,474,95,819,116,383,327,676,553,513,
%T A114645 107,126,214,352,428,710,485,752,97,151,419,430,383,886,71,677,721,
%U A114645 533,554,431,671,88,631,342,177,272,684,354,555,368,709,111,73,741,823,214,748
%N A114645 The numbers 2^n-1 written in groups of three digits, with leading zeros omitted.
%D A114645 Heard over coffee at the Computers in Scientific Discovery meeting in Ghent, Feb 02 2006.
%H A114645 Alois P. Heinz, <a href="/A114645/b114645.txt">Table of n, a(n) for n = 1..10000</a>
%e A114645 1,3,7,15,31,63,...
%t A114645 FromDigits[#] & /@ Partition[ Flatten[ IntegerDigits[ Table[ 2^n - 1, {n, 31}]]], 3] (* _Robert G. Wilson v_, Jun 23 2014 *)
%o A114645 (Python)
%o A114645 from itertools import count, islice
%o A114645 def bgen(): yield from (d for n in count(1) for d in str((1 << n)-1))
%o A114645 def agen(): g = bgen(); yield from (int("".join(t)) for t in zip(g, g, g))
%o A114645 print(list(islice(agen(), 54))) # _Michael S. Branicky_, Dec 25 2022
%K A114645 nonn,base,dumb
%O A114645 1,1
%A A114645 _N. J. A. Sloane_, Feb 18 2006
%E A114645 More terms from _Matthew Conroy_, Mar 12 2006