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 A319181 #4 Sep 15 2018 15:48:26 %S A319181 3,5,7,11,13,17,19,21,23,29,31,37,39,41,43,47,53,57,59,61,63,65,67,71, %T A319181 73,79,83,87,89,91,97,101,103,107,109,111,113,115,117,127,129,131,133, %U A319181 137,139,147,149,151,157,159,163,167,171,173,179,181,183,185,189 %N A319181 Numbers that are not perfect powers but whose prime indices have a common divisor > 1. %C A319181 A prime index of n is a number m such that prime(m) divides n. %e A319181 The sequence of integer partitions whose Heinz numbers are in the sequence begins: (2), (3), (4), (5), (6), (7), (8), (4,2), (9), (10), (11), (12), (6,2), (13), (14), (15), (16), (8,2), (17), (18), (4,2,2), (6,3). %t A319181 Select[Range[1000],And[GCD@@PrimePi/@FactorInteger[#][[All,1]]>1,GCD@@FactorInteger[#][[All,2]]==1]&] %Y A319181 Cf. A007916, A056239, A072774, A289509, A298748, A319161, A319163, A319165, A319179, A319180. %K A319181 nonn %O A319181 1,1 %A A319181 _Gus Wiseman_, Sep 12 2018