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 A122444 #7 Mar 04 2017 10:12:38 %S A122444 1,2,3,3,5,7,5,2,7,11,5,13,11,17,7,3,19,13,23,7,17,11,19,29,31,2,13, %T A122444 23,37,11,3,41,17,43,29,13,31,47,19,5,53,37,23,59,17,11,61,41,43,19, %U A122444 67,47,71,13,29,73,31,79,53,23,83 %N A122444 Greatest prime factor of powers of semiprimes. %C A122444 A122443 is least prime factor of powers of semiprimes. Cf. A076397 Largest prime factor of n-th perfect power. %H A122444 Michael De Vlieger, <a href="/A122444/b122444.txt">Table of n, a(n) for n = 1..10000</a> %F A122444 a(n) = A006530(A085155(n)) = greatest prime factor of A085155 powers of semiprimes. %t A122444 FactorInteger[#][[-1, 1]] & /@ Select[Range@ 168, Function[n, Or[n == 1, And[Length@ # == 1, EvenQ@ First@ #], And[Length@ # == 2, SameQ @@ #]] &[FactorInteger[n][[All, -1]]]]] (* _Michael De Vlieger_, Mar 04 2017 *) %Y A122444 Cf. A000040, A001358, A006530, A020639, A076396, A076397, A085155, A122443. %K A122444 easy,nonn %O A122444 1,2 %A A122444 _Jonathan Vos Post_, Sep 06 2006