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 A337648 #26 Oct 21 2020 20:32:12
%S A337648 3,19,59,73,83,89,127,131,137,149,151,157,163,193,223,227,229,239,241,
%T A337648 251,257,263,269,271,277,281,283,293,307,311,313,317,331,337,347,349,
%U A337648 353,359,373,379,383,389,397,401,409,419,421,431,433,439,443,449,457,461,463,467,479,487,491
%N A337648 Odd primes p such that the first term in A336957 that is divisible by p is 2*p.
%C A337648 Conjecture 1: this sequence contains all primes > 367.
%C A337648 Conjecture 2: The set of odd primes is partitioned into A337648, A337649, and {7}.
%C A337648 (These conjectures have been checked for the first 161734 terms of A336957.)
%C A337648 When an odd prime p first divides a term of A336957 that term is equal to q*p where q < p is also a prime. It appears q is almost always 2 (the corresponding values of p form the present sequence), that there are 34 instances when q = 3 (see A337649), and q>3 happens just once, at A336957(5) = 35 when q=5 and p=7.
%C A337648 See also the comment in A336957 discussing when primes first appear in A336957.
%Y A337648 Cf. A336957, A337275, A337649.
%K A337648 nonn
%O A337648 1,1
%A A337648 _N. J. A. Sloane_, Sep 26 2020