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 A069522 #9 Aug 06 2019 06:12:12 %S A069522 3,12,3,12,30,12,21,120,0,30,0,12,10101,210,30,1200,102,0,11001,120, %T A069522 21,0,2001,120,300,101010,0,2100,2001,30,10000011,12000,0,102,210,0, %U A069522 111,110010,10101,120,0,210,100100001,0,0,20010,10011,1200,1100001,300,102 %N A069522 Smallest multiple of n with digit sum = 3, or 0 if no such number exists, e.g. a(9k)= 0 = a(11k). %C A069522 a(9k)=a(11k)=a(41k)=a(73k)=a(79k)=a(101k)=0 - _Ray Chandler_, Jul 30 2003 %C A069522 a(2^k)=1.2*10^k [From _David Brown_, Dec 19 2009] %F A069522 a(n) = n*A088392(n) . - _R. J. Mathar_, Aug 06 2019 %Y A069522 Cf. A069521. %K A069522 base,nonn %O A069522 1,1 %A A069522 _Amarnath Murthy_, Apr 01 2002 %E A069522 More terms from _Ray Chandler_, Jul 30 2003