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 A074157 #35 Jun 15 2025 19:37:52 %S A074157 2,4,6,8,10,12,14,16,18,0,22,36,26,28,30,32,34,36,38,0,63,44,46,96, %T A074157 100,78,54,56,58,0,62,64,66,68,70,72,111,76,78,0,82,168,86,88,90,92, %U A074157 188,96,588,0,204,104,106,108,110,112,114,116,118,0,244,310,189,128 %N A074157 Smallest multiple of n which uses no digits of n, or 0 if no such number exists. %C A074157 For numbers n of the form 10k, of the form 10k+5 with a zero somewhere, and those using all 10 digits, a(n) = 0. %C A074157 Are there numbers using 8 of the 9 nonzero digits for which a(n) is nonzero? If so, what is the smallest such number? %C A074157 All such numbers have a(n) nonzero since a candidate value for a(n) is d*A052983(n) where d is the nonzero digit not in n. - _Gonzalo MartÃnez_, Dec 12 2024 %H A074157 Michel Marcus, <a href="/A074157/b074157.txt">Table of n, a(n) for n = 1..1000</a> %o A074157 (PARI) a(n) = if(!(n%10), return(0)); my(dn = Set(digits(n))); if(#dn==10 || (#dn==9 && dn[1]==1), return(0)); if(!(n%5) && !dn[1], return(0)); if(!(n%2), my(v=setminus([0, 2, 4, 6, 8], dn)); if(!#v || (#v==1 && #dn==9 && valuation(n, 2)>valuation(v[1], 2)) || (v==[2, 6] && #dn==8 && valuation(n, 2)>1), return(0))); forstep(m=2*n, oo, n, if(!#setintersect(Set(digits(m)), dn), return(m))); \\ _Michel Marcus_, Aug 04 2017 (Corrected by _Jinyuan Wang_, Jun 15 2025) %Y A074157 Cf. A052983, A076924, A378865. %K A074157 nonn,base %O A074157 1,1 %A A074157 _Amarnath Murthy_, Aug 29 2002 %E A074157 a(24) and a(49) corrected by _Michel Marcus_, Aug 04 2017