cp's OEIS Frontend

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.

A333201 Rectangular array read by antidiagonals: row n shows the numbers k such that p(k) = prime(k-1) + 2n, where prime(k) = k-th prime, with 1 prefixed to row 1.

Original entry on oeis.org

1, 2, 5, 3, 7, 10, 4, 9, 12, 25, 6, 13, 16, 73, 35, 8, 15, 17, 78, 43, 47, 11, 20, 19, 80, 54, 48, 31, 14, 23, 22, 88, 62, 92, 63, 283, 18, 26, 24, 93, 69, 98, 67, 296, 100, 21, 28, 33, 95, 81, 115, 138, 320, 181, 155, 27, 30, 37, 125, 83, 122, 147, 332, 206
Offset: 1

Views

Author

Clark Kimberling, May 11 2020

Keywords

Comments

Every positive integer occurs exactly once, so that as a sequence, this is a permutation of the positive integers. Row 1: A107770, except for initial 1,2.

Examples

			Northwest corner:
    1      2     3     4     6    8    11   14   18   21
    5      7     9    13    15   20    23   26   28   30
   10     12    16    17    19   22    24   33   37   38
   25     73    78    80    88   93    95  125  127  129
   35     43    54    62    69   81    83  102  107  116
		

Crossrefs

Programs

  • Mathematica
    z = 2700; p = Prime[Range[z]];
    r[n_] := Select[Range[z], p[[#]] - p[[# - 1]] == 2 n &]; r[1] = Join[{1, 2}, r[1]];
    TableForm[Table[Prime[r[n]], {n, 1, 18}]]  (* A333200, array *)
    TableForm[Table[r[n], {n, 1, 18}]] (* A333201, array *)
    Table[Prime[r[n - k + 1][[k]]], {n, 12}, {k, n, 1, -1}] // Flatten (* A333200, sequence *)
    Table[r[n - k + 1][[k]], {n, 12}, {k, n, 1, -1}] // Flatten (* A333201, sequence *)