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 A109513 #14 Dec 17 2023 12:25:37
%S A109513 1,19,94,3542,7295,318320,927130,939240,688370303,7682437410,
%T A109513 7996237896,89594051933
%N A109513 Let k be an m-digit integer. Then k is a Pithy number if the k-th m-tuple in the decimal digits of Pi (after the decimal point) is the string k.
%H A109513 David G. Andersen, <a href="http://www.angio.net/pi/piquery">The Pi-Search Page</a>.
%e A109513 1 is a term because the first digit in Pi (after the decimal point) is 1.
%e A109513 19 is a term because the 19th pair of digits (after the decimal point) in Pi is 19:
%e A109513 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19
%e A109513 3. 14 15 92 65 35 89 79 32 38 46 26 43 38 32 79 50 28 84 19 ...
%t A109513 PithyNumbers[m_] := Module[{cc = m(10^m)+m, sol, aa}, sol = Partition[RealDigits[Pi, 10, cc] // First // Rest, m]; Do[aa = FromDigits[sol[[i]]]; If[aa==i, Print[{i, aa}]], {i, Length[sol]}];] Example: PithyNumbers[4] produces all 4-digit Pithy numbers
%Y A109513 Cf. A000796, A109514, A057679, A057680.
%K A109513 base,more,nonn
%O A109513 0,2
%A A109513 _Colin Rose_, Jul 01 2005
%E A109513 a(8)-a(11) from _J. Volkmar Schmidt_, Dec 17 2023