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 A350705 #25 Mar 17 2022 13:51:35 %S A350705 169,221,247,289,323,361,403,481,527,559,589,629,703,731,793,817,871, %T A350705 923,949,961,1027,1037,1139,1147,1159,1207,1241,1261,1273,1313,1333, %U A350705 1339,1343,1349,1369,1387,1417,1501,1591,1649,1651,1717,1751,1781,1807,1843,1849,1853 %N A350705 Composite numbers that have no Sophie Germain prime and no "safe prime" factors. %C A350705 Prime factors of the terms have to be in A059500. %H A350705 Karl-Heinz Hofmann, <a href="/A350705/b350705.txt">Table of n, a(n) for n = 1..10000</a> %e A350705 a(2) = 221 = 13 * 17 and {13, 17} are neither in A005384 nor in A005385, but they are in A059500. %t A350705 Select[Range[2000], CompositeQ[#] && AllTrue[FactorInteger[#][[;; , 1]], ! PrimeQ[2*#1 + 1] && ! PrimeQ[(#1 - 1)/2] &] &] (* _Amiram Eldar_, Feb 15 2022 *) %o A350705 (Python) %o A350705 from sympy import primefactors, isprime %o A350705 print([n for n in range(2,1854) if not isprime(n) and all(not isprime(p*2+1) and not isprime((p-1)//2) for p in primefactors(n))]) %o A350705 (PARI) isok(m) = if ((m>1) && !isprime(m), my(f=factor(m)[,1]); !#select(x->isprime(2*x+1), f) && !#select(x->isprime((x-1)/2), f)); \\ _Michel Marcus_, Feb 14 2022 %Y A350705 Subsequence of A350704 and A350706. %Y A350705 Cf. A005384, A005385, A053176, A059500. %K A350705 nonn %O A350705 1,1 %A A350705 _Karl-Heinz Hofmann_, Feb 14 2022