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 A194262 #21 May 30 2015 22:09:56 %S A194262 1,2,3,5,7,11,1,1,1,1,1,1,101,1,1,1,1,1,1,19,1,167,251,1,89,29,43,13, %T A194262 83,467,311,23,1,1231,41,17977,281,1,1,127,193,2417,71,97,1087,241,67, %U A194262 7013,631,9283,661,53,5237,59,227,1019,102359,3251,199,409,971 %N A194262 Largest prime that divides the n-th partition number p(n) but does not divide p(1)*p(2)*...*p(n-1), or 1 if none. %C A194262 It appears that a(n) is prime for all n > 97. See A194259 and A194260 for additional comments and links. %H A194262 Alois P. Heinz and Giovanni Resta, <a href="/A194262/b194262.txt">Table of n, a(n) for n = 1..10000</a> (first 2000 terms from Alois P. Heinz) %p A194262 with(combinat): with(numtheory): %p A194262 b:= proc(n) option remember; %p A194262 `if`(n=1, {}, b(n-1) union factorset(numbpart(n))) %p A194262 end: %p A194262 a:= n-> `if`(n=1, 1, max(1, (b(n) minus b(n-1))[])): %p A194262 seq(a(n), n=1..120); # _Alois P. Heinz_, Aug 21 2011 %t A194262 a[n_] := Complement[FactorInteger[PartitionsP[n]][[All, 1]], FactorInteger[Product[PartitionsP[k], {k, 1, n-1}]][[All, 1]]] /. {} -> {1} // Last; Table[a[n], {n, 1, 100}] (* _Jean-François Alcover_, Jan 28 2014 *) %Y A194262 Cf. A000041, A071963, A194259, A194260, A194261. %K A194262 nonn,look %O A194262 1,2 %A A194262 _Jonathan Sondow_, Aug 21 2011