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 A005606 M4958 #31 Aug 27 2023 19:28:56
%S A005606 26,15,20,20,6,6,19,19,5,14,20,5,20,20,6,6,19,19,5,14,20,20,20,20,20,
%T A005606 20,20,20,20,20,20,20,20,20,20,20,20,20,20,20,6,6,6,6,6,6,6,6,6,6,6,6,
%U A005606 6,6,6,6,6,6,6,6,19,19,19,19,19,19,19,19,19,19,19,19,19,19,19,19,19,19
%N A005606 Position of first letter of n (in English) in alphabet.
%C A005606 English name for n begins with a(n)-th letter.
%D A005606 N. J. A. Sloane and Simon Plouffe, The Encyclopedia of Integer Sequences, Academic Press, 1995 (includes this sequence).
%H A005606 Harvey P. Dale, <a href="/A005606/b005606.txt">Table of n, a(n) for n = 0..1000</a>
%H A005606 Chris Cole, <a href="/A005606/a005606.pdf">Email to N. J. A. Sloane, Apr 23 1994</a> (contains many letter sequences, including the letter equivalent of A005606).
%e A005606 'One' begins with 'O' and 'O' is the fifteenth letter hence a(1)=15.
%t A005606 Table[LetterNumber[Characters[IntegerName[n,"Words"]][[1]]],{n,0,80}] (* _Harvey P. Dale_, Jun 06 2016 *)
%o A005606 (Python)
%o A005606 from num2words import num2words
%o A005606 def a(n): return ord(num2words(n)[0]) - 96
%o A005606 print([a(n) for n in range(78)]) # _Michael S. Branicky_, Jul 12 2022
%K A005606 word,nonn,nice,easy
%O A005606 0,1
%A A005606 _N. J. A. Sloane_
%E A005606 More terms from Larry Reeves (larryr(AT)acm.org), Oct 02 2000