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.

A264731 Rectangular array A read by upward antidiagonals in which the entry in row n and column k is defined by A(n,k) = prime(2^(n-1)*(2*k-1)), n,k >= 1.

Original entry on oeis.org

2, 3, 5, 7, 13, 11, 19, 37, 29, 17, 53, 89, 71, 43, 23, 131, 223, 173, 107, 61, 31, 311, 503, 409, 263, 151, 79, 41, 719, 1163, 941, 613, 359, 193, 101, 47, 1619, 2657, 2129, 1423, 827, 457, 239, 113, 59, 3671, 5849, 4751, 3167, 1877, 1049, 569, 281, 139, 67
Offset: 1

Views

Author

L. Edson Jeffery, Nov 22 2015

Keywords

Comments

Every primes appears exactly once in the array.

Examples

			The array begins:
.     2      5     11     17     23     31     41     47     59      67
.     3     13     29     43     61     79    101    113    139     163
.     7     37     71    107    151    193    239    281    337     383
.    19     89    173    263    359    457    569    659    769     881
.    53    223    409    613    827   1049   1283   1511   1747    2003
.   131    503    941   1423   1877   2377   2861   3413   3923    4481
.   311   1163   2129   3167   4211   5309   6379   7561   8731    9857
.   719   2657   4751   6971   9311  11731  14143  16603  19183   21661
.  1619   5849  10459  15331  20393  25579  30859  36161  41611   47143
.  3671  12907  22943  33479  44269  55487  66791  78193  89899  101573
As a triangle:
.    2
.    3    5
.    7   13   11
.   19   37   29   17
.   53   89   71   43   23
.  131  223  173  107   61  31
.  311  503  409  263  151  79  41
...
		

Crossrefs

Cf. A031368, A031378, A031395 (rows 1--3).
Cf. A033844 (column 1).
Cf. A264735 (main diagonal).

Programs

  • Mathematica
    (* Array: *)
    Grid[Table[Prime[2^(n - 1)*(2*k - 1)], {n, 10}, {k, 10}]]
    (* Array antidiagonals flattened: *)
    Flatten[Table[Prime[2^(n - k)*(2*k - 1)], {n, 10}, {k, n}]]

Formula

A(n,k) = A000040(A054582(n-1,k-1)).
A(A001511(m),A003602(m)) = A000040(m), m >= 1.