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 A377366 #4 Nov 04 2024 22:29:37
%S A377366 1,1,1,1,1,4,2,1,1,1,1,1,1,1,2,1,1,2,4,1,2,4,2,3,1,2,2,2,1,1,1,1,1,1,
%T A377366 1,1,2,1,2,2,1,2,1,1,6,2,1,1,1,2,1,2,1,5,1,1,1,1,1,1,1,2,1,1,3,1,1,2,
%U A377366 2,1,4,10,4,6,2,1,2,1
%N A377366 Rectangular array by antidiagonals: R(m,n) = least k such that 2n*prime(m)^k - 1 is prime.
%e A377366 Corner:
%e A377366 1 1 1 2 1 1 4 1 2 2 1 1 2 3 1 2
%e A377366 1 1 1 1 1 2 1 1 1 1 2 1 2 1 1 3
%e A377366 4 1 1 2 3 1 2 1 1 2 1 2 4 1 1 8
%e A377366 1 1 4 1 1 2 1 1 1 3 1 1 2 1 1 2
%e A377366 2 1 2 1 1 2 1 4 1 1 1 3 18 1 2 1
%e A377366 2 2 1 2 1 1 10 1 1 1 2 1 2 6 1 2
%e A377366 2 1 1 2 2 4 1 4 2 1 3 7 1 4 1 8
%e A377366 1 1 1 1 6 6 1 2 3 1 1 1 11 1 6 1
%e A377366 6 5 1 2 1 1 2 4 7 1 2 1 2 1 3 4
%e A377366 1 3 1 10 1 1 2 1 2 6 2 1 2 5 8 2
%e A377366 1 2 1 1 1 1 1 1 9 1 2 1 1 2 3 2
%e A377366 1 3 4 1 3 14 1 1 2 1 8 7 2 1 1 3
%e A377366 2 1 1 1 4 2 3 1 1 2 14 7 1 6 2 1
%e A377366 2 1 1 1 1 1 1 1 2 7 3 1 4 3 1 3
%e A377366 4 1 1 1 2 2 1 3 1 2 1 7 8 1 1 1
%e A377366 1 1 8 15 1 2 4 1 9 4 1 1 2 1 1 2
%t A377366 f[m_, n_, k_] := 2 n*Prime[m]^k - 1;
%t A377366 s[m_, n_] := Select[Range[20], PrimeQ[f[m, n, #]] &, 1]
%t A377366 u[m_] := Flatten[Table[s[m, n], {n, 1, 60}]]
%t A377366 Column[Table[Take[u[m], 16], {m, 1, 16}]]
%t A377366 r[m_] := Take[u[m], 12]; w[m_, n_] := r[m][[n]];
%t A377366 Table[w[m, n], {m, 1, 16}, {n, 1, 12}] (* array *)
%t A377366 Table[w[n - k + 1, k], {n, 12}, {k, n, 1, -1}] // Flatten (* sequence *)
%Y A377366 Cf. A000040, A377367.
%K A377366 nonn,tabl
%O A377366 1,6
%A A377366 _Clark Kimberling_, Oct 31 2024