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 A370745 #8 Feb 29 2024 06:22:11
%S A370745 4,6,8,12,14,18,20,24,28,30,32,36,38,42,44,48,54,60,62,68,72,74,76,80,
%T A370745 84,90,96,98,102,104,108,110,114,124,128,132,138,140,144,148,150,152,
%U A370745 158,160,164,168,174,180,182,186,192,194,196,198,200,204,210,212,220
%N A370745 Numbers k that have at least one divisor d such that p = k/d-1 is prime and (2*d)|(p-1).
%C A370745 All the terms are even.
%C A370745 Includes all the numbers of the form p+1 where p is an odd prime (A008864 \ {3}).
%H A370745 Amiram Eldar, <a href="/A370745/b370745.txt">Table of n, a(n) for n = 1..10000</a>
%H A370745 D. R. Heath-Brown, Cheryl E. Praeger and Aner Shalev, <a href="https://doi.org/10.1007/BF02775443">Permutation groups, simple groups, and sieve methods</a>, Isr. J. Math., Vol. 148 (2005), pp. 347-375; <a href="https://core.ac.uk/download/pdf/96673.pdf">alternative link</a>.
%F A370745 The number of terms that do not exceed x is N(x) = h * x/log(x) + O(x/log(x)^2), where h = A370746.
%t A370745 q[n_] := AnyTrue[Divisors[n], PrimeQ[n/# - 1] && Divisible[n/# - 2, 2*#] &]; Select[Range[250], q]
%o A370745 (PARI) is(n) = {my(d = divisors(n)); for(i=1, #d, if(isprime(n/d[i]-1) && !((n/d[i]-2) % (2*d[i])), return(1))); 0;}
%Y A370745 Cf. A008864, A370746.
%K A370745 nonn,easy
%O A370745 1,1
%A A370745 _Amiram Eldar_, Feb 29 2024