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 A097963 #13 Aug 31 2021 04:09:43
%S A097963 1,15,26,40,50,60,70,82,97,113,137,165,190,213,237,265,290,313,339,
%T A097963 367,396,424,452,479,507,529,556,582,610,629,655,680,703,724,753,780,
%U A097963 805,826,854,882,911,934,962,989,1016,1040,1063,1089,1116,1152,1191,1230
%N A097963 ["comma"], is the first, fifteenth, twenty-sixth, fortieth, ... character in this sentence, including spaces and punctuations.
%C A097963 Yes, the definition begins with a comma!
%H A097963 Jon E. Schoenfield, <a href="/A097963/b097963.txt">Table of n, a(n) for n = 1..1000</a>
%F A097963 After a(2) = 15, the remaining terms are given by the recursion a(n+1) = a(n) + 2 + length(OrdinalName(a(n))); e.g., a(3) = a(2) + 2 + length(OrdinalName(a(2))) = 15 + 2 + length("fifteenth") = 15 + 2 + 9 = 26. - _Jon E. Schoenfield_, Aug 13 2007
%e A097963 Label the coordinates:
%e A097963 00000000011111111112222222222333333333344444444445...
%e A097963 12345678901234567890123456789012345678901234567890... Then (comma)
%e A097963 ["Comma"], is the first, fifteenth, twenty-sixth, fortieth, fiftieth, fifty-ninth, seventy-second, eighty-eighth, one hundred third, one hundred twenty-second, ... character.
%o A097963 (Python)
%o A097963 from itertools import accumulate, repeat
%o A097963 from num2words import num2words
%o A097963 A097963_list = [1]+list(accumulate(repeat(15,100), lambda x, _: x+2+len(num2words(x,to='ordinal').replace(' and ',' ').replace(', ',' ')))) # _Chai Wah Wu_, Aug 30 2021
%Y A097963 Cf. A055508, A005224, A049525.
%K A097963 nonn,base,nice,easy,word
%O A097963 1,2
%A A097963 _Ray G. Opao_, Sep 21 2004
%E A097963 Corrected and extended by _Jon E. Schoenfield_, Aug 13 2007