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 A247872 #16 Oct 15 2014 15:56:16 %S A247872 5,7,5,7,5,11,17,5,7,19,5,11,7,5,13,5,11,23,5,19,7,5,13,7,5,17,5,7,13, %T A247872 5,23,7,5,29,17,5,11,13,5,31,7,37,19,5,11,7,5,17,5,7,11,5,29,7,5,17, %U A247872 11,5,31,23,41,5,13,7,5,19,7,5,13,5,7,5,23,7,5,19,11,31,5,5,7,11,5,37,7,5,47,53,11,5,7,43,13,5,7 %N A247872 Least prime factor of A247681(n). %H A247872 Odimar Fabeny, <a href="/A247872/b247872.txt">Table of n, a(n) for n = 2..10000</a> %p A247872 count:= 0: %p A247872 for n from 1 while count < 100 do %p A247872 m:= 1+18*n; %p A247872 if not isprime(m) then %p A247872 count:= count+1; %p A247872 A[count]:= min(numtheory:-factorset(m)) %p A247872 fi %p A247872 od: %p A247872 seq(A[i],i=1..count); # _Robert Israel_, Sep 30 2014 %Y A247872 Cf. A056608, A247681. %K A247872 nonn,easy %O A247872 2,1 %A A247872 _Odimar Fabeny_, Sep 25 2014