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 A375906 #7 Sep 02 2024 08:40:11
%S A375906 1,2,4,5,8,9,10,14,18,20,21,24,25,28,32,33,35,38,42,43,44,51,52,54,55,
%T A375906 68,70,75,76,87,91,95,107,108,114,122,128,134,137,138,139,142,146,150,
%U A375906 154,156,162,176,177,187,193,198,206,214,232,234,237,242,246,248,250
%N A375906 Positions of primes in the sequence of numbers of the form 2^t * 3^u + 1 (A055600).
%H A375906 Amiram Eldar, <a href="/A375906/b375906.txt">Table of n, a(n) for n = 1..10000</a>
%F A375906 A055600(a(n)) = A003586(a(n)) + 1 = A005109(n).
%t A375906 With[{lim = 10^10}, Position[Sort@ Flatten@ Table[2^i*3^j + 1, {i, 0, Log2[lim]}, {j, 0, Log[3, lim/2^i]}], _?PrimeQ] // Flatten]
%o A375906 (PARI) lista(lim) = {my(s = List()); for(i = 0, logint(lim, 2), for(j = 0, logint(lim >> i, 3), listput(s, 2^i * 3^j + 1))); s = Set(s); for(i = 1, #s, if(isprime(s[i]), print1(i, ", ")));}
%Y A375906 Cf. A003586, A005109, A055600, A174099.
%K A375906 nonn
%O A375906 1,2
%A A375906 _Amiram Eldar_, Sep 02 2024