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 A171491 #21 Sep 05 2025 15:29:27 %S A171491 11,13,15,17,19,21,23,25,27,29,31,33,35,37,39,41,43,45,47,49,51,53,55, %T A171491 57,59,61,63,65,67,69,71,73,75,77,79,81,83,85,87,89,91,93,95,97,99, %U A171491 100,101,103,104,106,107,109,110,112,113,115,116,118,119,121,122,124,125 %N A171491 Natural numbers not divisible by their number of decimal digits. %C A171491 Complement of A098952. %C A171491 Asymptotic density 1. - _Charles R Greathouse IV_, Nov 13 2010 %H A171491 Michael S. Branicky, <a href="/A171491/b171491.txt">Table of n, a(n) for n = 1..10000</a> %e A171491 100 has three digits and is not divisible by 3, therefore 100 is in the sequence. %t A171491 Select[Range[150],!Divisible[#,IntegerLength[#]]&] (* _Harvey P. Dale_, Apr 24 2011 *) %o A171491 (Magma) [n: n in [1..140] | not IsIntegral(n/#Intseq(n))]; // _Bruno Berselli_, Feb 09 2016 %o A171491 (Python) %o A171491 def ok(n): return n%len(str(n)) %o A171491 print([k for k in range(142) if ok(k)]) # _Michael S. Branicky_, Feb 07 2022 %Y A171491 Cf. A098952. %K A171491 nonn,base,changed %O A171491 1,1 %A A171491 _Jaroslav Krizek_, Dec 10 2009