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 A337904 #22 Mar 21 2021 10:05:35
%S A337904 1,43,714,715,9763,122968,122969,1478366,17239955,196746419,
%T A337904 2209316467,24499118645,268950072605
%N A337904 Numbers k such that the decimal expansion of the k-th harmonic number starts with the digits of k, in the same order.
%C A337904 The sequence also includes 196746419, 2209316467, 24499118645, 268950072605, 2928264676792, 31663398162514, 340383084842938, 3640820101879826. - _Daniel Suteu_, Oct 01 2020
%e A337904 1/1 + 1/2 + 1/3 + ... + 1/1478366 = 14.78366... .
%t A337904 s=0;Do[s=s+(1/n);t=IntegerLength[n];m=IntegerLength[Floor[s]];k = Floor[s (10^(t-m))];If[k==n,Print[n]],{n,1,10^11}]
%o A337904 (PARI) lista(nn) = {my(s=0.); for (n=1, nn, s += 1./n; my(d = digits(floor(10^20*s))); if (fromdigits(vector(#Str(n), j, d[j])) == n, print1(n, ", ")););} \\ _Michel Marcus_, Sep 30 2020
%Y A337904 Cf. A033147, A055980.
%K A337904 nonn,base,more
%O A337904 1,2
%A A337904 _Metin Sariyar_, Sep 29 2020
%E A337904 a(9) from _Jinyuan Wang_, Sep 30 2020
%E A337904 a(10)-a(12) from _Chai Wah Wu_, Oct 12 2020
%E A337904 a(13) from _Chai Wah Wu_, Oct 14 2020