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 A361744 #60 Apr 07 2023 09:24:39
%S A361744 1,2,1,3,3,2,4,5,4,1,6,11,6,3,2,7,47,8,5,4,1,12,53,10,7,8,13,2,15,141,
%T A361744 16,9,20,21,6,3,16,143,18,15,38,33,30,7,1,18,191,20,23,64,81,162,39,3,
%U A361744 4,28,273,28,29,80,129,654,79,5,12,2
%N A361744 A(n,k) is the least m such that there are k primes in the set {prime(n) + 2^i | 1 <= i <= m}, or -1 if no such number exists; square array A(n,k), n > 1, k >= 1, read by antidiagonals.
%e A361744 p = prime(2) = 3, m=1, u = {p + 2^k | 1 <= k <= m} = {5} contains one prime, and no lesser m satisfies this, so A(2,1) = 1.
%e A361744 Square array A(n,k) n > 1 and k >= 1 begins:
%e A361744 1, 2, 3, 4, 6, 7, 12, 15, 16, 18, ...
%e A361744 1, 3, 5, 11, 47, 53, 141, 143, 191, 273, ...
%e A361744 2, 4, 6, 8, 10, 16, 18, 20, 28, 30, ...
%e A361744 1, 3, 5, 7, 9, 15, 23, 29, 31, 55, ...
%e A361744 2, 4, 8, 20, 38, 64, 80, 292, 1132, 4108, ...
%e A361744 1, 13, 21, 33, 81, 129, 285, 297, 769, 3381, ...
%e A361744 2, 6, 30, 162, 654, 714, 1370, 1662, 1722, 2810, ...
%e A361744 3, 7, 39, 79, 359, 451, 1031, 1039, 11311, 30227, ...
%e A361744 1, 3, 5, 7, 9, 13, 15, 17, 23, 27, ...
%o A361744 (PARI) A(n, k)= {my(nb=0, p=prime(n), m=1); while (nb<k, if (ispseudoprime(p+2^m), nb++); m++); m--}
%Y A361744 Cf. A057732 (1st row), A094076 (1st column).
%Y A361744 Cf. A361679.
%Y A361744 Cf. A019434 (primes 2^n+1), A057732 (2^n+3), A059242 (2^n+5), A057195 (2^n+7), A057196(2^n+9), A102633 (2^n+11), A102634 (2^n+13), A057197 (2^n+15), A057200 (2^n+17), A057221 (2^n+19), A057201 (2^n+21), A057203 (2^n+23).
%Y A361744 Cf. A205558 and A231232 (with 2*k instead of 2^k).
%K A361744 nonn,tabl
%O A361744 2,2
%A A361744 _Jean-Marc Rebert_, Mar 22 2023