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 A034048 #30 Feb 16 2025 08:32:36 %S A034048 0,10,20,25,30,40,45,50,52,54,55,56,58,59,60,65,69,70,78,80,85,87,90, %T A034048 95,96,100,101,102,103,104,105,106,107,108,109,110,120,125,130,140, %U A034048 145,150,152,154,155,156,158,159,160,165,169,170,178,180,185,187,190,195 %N A034048 Numbers with multiplicative digital root value 0. %C A034048 Numbers with root value 1 are the 'repunits' (see A000042). %C A034048 This sequence has density 1. - _Franklin T. Adams-Watters_, Apr 01 2009 %C A034048 Any integer with at least one 0 among its base 10 digits is in this sequence. - _Alonso del Arte_, Aug 29 2014 %C A034048 This sequence is 10-automatic: it contains numbers with a 0, or with a 5 and any even digit. - _Charles R Greathouse IV_, Feb 13 2017 %H A034048 Franklin T. Adams-Watters, <a href="/A034048/b034048.txt">Table of n, a(n) for n = 1..10000</a> %H A034048 Eric Weisstein's World of Mathematics, <a href="https://mathworld.wolfram.com/MultiplicativeDigitalRoot.html">Multiplicative Digital Root</a> %H A034048 <a href="/index/Ar#10-automatic">Index entries for 10-automatic sequences</a>. %e A034048 20 is in the sequence because 2 * 0 = 0. %e A034048 25 is in the sequence because 2 * 5 = 10 and 1 * 0 = 0. %t A034048 mdr0Q[n_]:=NestWhile[Times@@IntegerDigits[#]&,n,#>9&]==0; Select[Range[ 0,200],mdr0Q] (* _Harvey P. Dale_, Jul 21 2020 *) %o A034048 (PARI) is(n)=factorback(digits(n))==0 \\ _Charles R Greathouse IV_, Feb 13 2017 %Y A034048 Cf. A031347, A034048, A002275, A034049, A034050, A034051, A034052, A034053, A034054, A034055, A034056 (numbers having multiplicative digital roots 0-9). %Y A034048 Cf. the subsets A011540 and A008592. %K A034048 nonn,base,easy %O A034048 1,2 %A A034048 _Patrick De Geest_, Sep 15 1998