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 A302563 #29 Sep 13 2018 06:08:09 %S A302563 1,11,20,29,38,47,56,65,74,83,92,102,111,120,129,138,147,156,165,174, %T A302563 183,192,201,210,219,228,237,246,255,264,273,282,291,300,309,318,327, %U A302563 336,345,354,363,372,381,390,399,408,417,426,435,444 %N A302563 Numbers whose digital root is equal to their number of digits. %C A302563 Last term is a(111111111) = 999999999. - _Giovanni Resta_, Aug 16 2018 %e A302563 11 and 111 belong to the set as they both have the same number of digits as their digital root, respectively; 11 has two digits and also digital root two, and 111 has three digits and digital root three. 302563 does not belong to the set, since it has six digits and digital root one. %t A302563 Select[Range[1000], IntegerLength[#] == Mod[#-1, 9] + 1 &] (* _Giovanni Resta_, Aug 16 2018 *) %o A302563 (PARI) isok(n) = if(n, (n-1)%9+1) == #Str(n); \\ _Michel Marcus_, Aug 16 2018 %Y A302563 Cf. A010888, A055642, A098955. %K A302563 nonn,easy,fini,base %O A302563 1,2 %A A302563 _Halfdan Skjerning_, Aug 16 2018