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 A173529 #16 Jul 05 2019 16:07:05
%S A173529 1,2,3,4,5,6,7,8,9,2,3,4,5,6,7,8,9,10,3,4,5,6,7,8,9,10,11,4,5,6,7,8,9,
%T A173529 10,11,12,5,6,7,8,9,10,11,12,13,6,7,8,9,10,11,12,13,14,7,8,9,10,11,12,
%U A173529 13,14,15,8,9,10,11,12,13,14,15,16,9,10,11,12,13,14,15,16,17,2,3,4,5,6,7,8,9,10,3,4,5,6,7,8,9,10,11,4
%N A173529 a(n) = 1 + A053830(n-1), where A053830 is the sum of the digits of its argument in base 9.
%C A173529 If A053830 is regarded as a triangle then the rows converge to this sequence.
%C A173529 This is the case b=9 of a non-periodic sequence, with key formulas and definitions provided with b=5 in A173525. Case b=2 is in A063787, and cases b=3 to 8 are in A173523 to A173528.
%F A173529 a(n) = A053830(9^k + n - 1) where k >= ceiling(log_9(n/8)). - _R. J. Mathar_, Dec 09 2010
%t A173529 Table[1 + Plus@@IntegerDigits[n - 1, 9], {n, 90}] (* _Vincenzo Librandi_, Jul 01 2019 *)
%Y A173529 Cf. A000120, A053830, A063787, A173523, A173524, A173525, A173526, A173527, A173528.
%K A173529 nonn,base
%O A173529 1,2
%A A173529 _Omar E. Pol_, Feb 23 2010