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 A361679 #15 Mar 20 2023 13:35:19 %S A361679 3,3,5,3,7,11,3,5,13,17,5,7,11,19,29,3,11,13,23,37,41,3,7,29,31,29,43, %T A361679 59,7,11,19,41,37,53,67,71,11,13,23,37,47,43,59,79,101,7,29,37,29,43, %U A361679 71,67,71,97,107,5,37,59,61,53,67,107,73,89,103,137 %N A361679 A(n,k) is the n-th prime p such that p + 2^k is also prime; square array A(n,k), n>=1, k>=1, read by antidiagonals. %H A361679 Alois P. Heinz, <a href="/A361679/b361679.txt">Antidiagonals n = 1..200, flattened</a> %e A361679 Square array A(n,k) begins: %e A361679 3, 3, 3, 3, 5, 3, 3, 7, 11, 7, ... %e A361679 5, 7, 5, 7, 11, 7, 11, 13, 29, 37, ... %e A361679 11, 13, 11, 13, 29, 19, 23, 37, 59, 67, ... %e A361679 17, 19, 23, 31, 41, 37, 29, 61, 89, 73, ... %e A361679 29, 37, 29, 37, 47, 43, 53, 97, 101, 79, ... %e A361679 41, 43, 53, 43, 71, 67, 71, 103, 107, 127, ... %e A361679 59, 67, 59, 67, 107, 73, 83, 127, 131, 139, ... %e A361679 71, 79, 71, 73, 131, 103, 101, 163, 149, 157, ... %e A361679 101, 97, 89, 97, 149, 109, 113, 193, 179, 163, ... %e A361679 107, 103, 101, 151, 167, 127, 149, 211, 197, 193, ... %p A361679 A:= proc() option remember; local f; f:= proc() [] end; %p A361679 proc(n, k) option remember; local p; %p A361679 p:= `if`(nops(f(k))=0, 1, f(k)[-1]); %p A361679 while nops(f(k))<n do p:= nextprime(p); %p A361679 if isprime(p+2^k) then f(k):= [f(k)[], p] fi %p A361679 od; f(k)[n] %p A361679 end %p A361679 end(): %p A361679 seq(seq(A(n, 1+d-n), n=1..d), d=1..12); %Y A361679 Columns k=1-10 give: A001359, A023200, A023202, A049488, A049489, A049490, A049491, A361483, A361484, A361485. %Y A361679 Row n=1 gives A056206. %Y A361679 Main diagonal gives A361680. %Y A361679 Cf. A000040. %K A361679 nonn,look,tabl %O A361679 1,1 %A A361679 _Alois P. Heinz_, Mar 20 2023