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 A277971 #13 Dec 20 2021 05:28:46
%S A277971 1,2,3,8,9,10,12,13,14,15,24,25,26,27,28,29,30,31,32,33,34,35,36,37,
%T A277971 38,39,40,41,42,43,44,45,46,47,48,49,50,51,52,53,54,55,56,57,58,59,64,
%U A277971 65,66,67,68,69,70,71,72,73,74,75,76,77,78,79,86,87,88,89,90,91
%N A277971 a(1) = 1; a(n) > a(n-1) is the smallest number whose name in English contains the first letter of the name of a(n-1).
%t A277971 name[n_]:=IntegerName[n,"Words"];a[1]=1;
%t A277971 a[n_]:=a[n]=Module[{i=a[n-1]+1},While[
%t A277971 !StringContainsQ[name[i],StringTake[name[a[n-1]],1]],i++ ];i];
%t A277971 a/@Range[68] (* _Ivan N. Ianakiev_, Dec 20 2021 *)
%Y A277971 Cf. A277972.
%K A277971 easy,nonn,word
%O A277971 1,2
%A A277971 _Ivan N. Ianakiev_, Nov 07 2016