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 A318981 #4 Sep 07 2018 04:44:42 %S A318981 1,6,12,14,15,18,21,24,26,28,30,35,36,38,39,42,45,48,51,52,54,56,58, %T A318981 60,63,65,66,69,70,72,74,75,76,77,78,84,86,87,90,91,95,96,98,102,104, %U A318981 105,106,108,111,112,114,116,117,119,120,122,123,126,130,132,133 %N A318981 Numbers whose prime indices plus 1 are relatively prime. %C A318981 A prime index of n is a number m such that prime(m) divides n. %e A318981 The sequence of integer partitions whose Heinz numbers are in the sequence begins: (), (21), (211), (41), (32), (221), (42), (2111), (61), (411), (321), (43), (2211), (81), (62), (421), (322), (21111). %t A318981 Select[Range[100],GCD@@(PrimePi/@FactorInteger[#][[All,1]]+1)==1&] %Y A318981 Cf. A000837, A007359, A018783, A281116, A289508, A289509, A318978, A318980. %K A318981 nonn %O A318981 1,2 %A A318981 _Gus Wiseman_, Sep 06 2018