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A049525 I is the first, second, eighth, ... letter in this sentence not counting spaces or commas.

%I A049525 #18 Feb 16 2025 12:40:49
%S A049525 1,2,8,19,25,41,51,56,61,66,71,76,81,86,91,103,115,120,126,131,137,
%T A049525 142,148,164,178,201,222,238,243,259,307,323,351,367,405,410,432,446,
%U A049525 451,494,510,515,532,555,588,615,631,636,652,664,680,691,700,712,723,734
%N A049525 I is the first, second, eighth, ... letter in this sentence not counting spaces or commas.
%e A049525 The sentence begins:
%e A049525 1234567890 1234567890 1234567890 1234567890 1234567890
%e A049525 Iisthefirs tsecondeig hthninetee nthtwentyf ifthfortyf
%e A049525 irstfiftyf irstfiftys ixthsixtyf irstsixtys ixthsevent
%e A049525 yfirstseve ntysixthei ghtyfirste ightysixth ninetyfirs
%e A049525 tonehundre dthirdoneh undredfift eenthonehu ndredtwent
%e A049525 iethonehun dredtwenty sixthonehu ndredthirt yfirstoneh
%e A049525 undredthir tyseventho nehundredf ortysecond onehundred ...
%t A049525 seed="iisthe";s[1]=1;s[2]=2; name[n_]:=
%t A049525 StringReplace[IntegerName[n,{"English","Ordinal"}],{"-"->""," "->""}];
%t A049525 s[n_]:=seed=StringJoin[seed<>name[StringPosition[seed,"i"][[n-2,1]]]];
%t A049525 l=s/@Range[56]; Table[StringPosition[Last[l],"i"][[k,1]],{k,1,Length[l]}]
%t A049525 (* _Ivan N. Ianakiev_, Apr 02 2022 *)
%o A049525 (Python)
%o A049525 from num2words import num2words
%o A049525 from itertools import islice
%o A049525 def n2w(n):
%o A049525     os = num2words(n, ordinal=True).replace(" and", "")
%o A049525     return os.replace(" ", "").replace("-", "").replace(chr(44), "")
%o A049525 def agen(): # generator of terms
%o A049525     s, idx = "iisthe", 0
%o A049525     while True:
%o A049525         idx_rel = 1 + s.index("i")
%o A049525         idx += idx_rel
%o A049525         yield idx
%o A049525         s = s[idx_rel:] + n2w(idx)
%o A049525 print(list(islice(agen(), 56))) # _Michael S. Branicky_, Apr 02 2022
%Y A049525 Cf. A005224, A055508.
%K A049525 nonn,word,easy,nice
%O A049525 1,2
%A A049525 _J. Lowell_
%E A049525 More terms from _Robert G. Wilson v_, Jul 18 2000
%E A049525 Corrected and extended by Larry Reeves (larryr(AT)acm.org), Nov 02 2000