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 A302540 #14 Feb 02 2021 04:33:59
%S A302540 1,2,3,4,5,6,8,9,10,11,12,15,16,17,18,20,22,24,25,27,30,31,32,33,34,
%T A302540 36,40,41,44,45,48,50,51,54,55,59,60,62,64,66,67,68,72,75,80,81,82,83,
%U A302540 85,88,90,93,96,99,100,102,108,109,110,118,120,121,123,124
%N A302540 Numbers whose prime indices other than 1 are prime numbers.
%C A302540 A prime index of n is a number m such that prime(m) divides n.
%H A302540 Andrew Howroyd, <a href="/A302540/b302540.txt">Table of n, a(n) for n = 1..1000</a>
%F A302540 Sum_{n>=1} 1/a(n) = 2 * Sum_{n>=1} 1/A076610(n) = 2 * Product_{p in A006450} p/(p-1) converges since the sum of the reciprocals of A006450 converges. - _Amiram Eldar_, Feb 02 2021
%t A302540 Select[Range[400],#===1||And@@(#===1||PrimeQ[#]&)/@PrimePi/@FactorInteger[#][[All,1]]&]
%o A302540 (PARI) ok(n)={!#select(p->p>2 && !isprime(primepi(p)), factor(n)[,1])} \\ _Andrew Howroyd_, Aug 26 2018
%Y A302540 Cf. A000961, A001222, A003963, A005117, A006450, A007716, A056239, A076610, A275024, A281113, A291686, A302242, A302243, A302534, A302539.
%K A302540 nonn
%O A302540 1,2
%A A302540 _Gus Wiseman_, Apr 09 2018