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.

A285723 Transpose of square array A285722.

Original entry on oeis.org

0, 1, 1, 3, 0, 2, 6, 2, 3, 4, 10, 5, 0, 5, 7, 15, 9, 4, 6, 8, 11, 21, 14, 8, 0, 9, 12, 16, 28, 20, 13, 7, 10, 13, 17, 22, 36, 27, 19, 12, 0, 14, 18, 23, 29, 45, 35, 26, 18, 11, 15, 19, 24, 30, 37, 55, 44, 34, 25, 17, 0, 20, 25, 31, 38, 46, 66, 54, 43, 33, 24, 16, 21, 26, 32, 39, 47, 56, 78, 65, 53, 42, 32, 23, 0, 27, 33, 40, 48, 57, 67, 91, 77, 64, 52, 41, 31, 22, 28, 34, 41, 49, 58, 68, 79
Offset: 1

Views

Author

Antti Karttunen, May 03 2017

Keywords

Comments

See A285722.

Examples

			The top left 14 X 14 corner of the array:
   0,  1,  3,  6, 10, 15, 21, 28, 36, 45, 55, 66, 78, 91
   1,  0,  2,  5,  9, 14, 20, 27, 35, 44, 54, 65, 77, 90
   2,  3,  0,  4,  8, 13, 19, 26, 34, 43, 53, 64, 76, 89
   4,  5,  6,  0,  7, 12, 18, 25, 33, 42, 52, 63, 75, 88
   7,  8,  9, 10,  0, 11, 17, 24, 32, 41, 51, 62, 74, 87
  11, 12, 13, 14, 15,  0, 16, 23, 31, 40, 50, 61, 73, 86
  16, 17, 18, 19, 20, 21,  0, 22, 30, 39, 49, 60, 72, 85
  22, 23, 24, 25, 26, 27, 28,  0, 29, 38, 48, 59, 71, 84
  29, 30, 31, 32, 33, 34, 35, 36,  0, 37, 47, 58, 70, 83
  37, 38, 39, 40, 41, 42, 43, 44, 45,  0, 46, 57, 69, 82
  46, 47, 48, 49, 50, 51, 52, 53, 54, 55,  0, 56, 68, 81
  56, 57, 58, 59, 60, 61, 62, 63, 64, 65, 66,  0, 67, 80
  67, 68, 69, 70, 71, 72, 73, 74, 75, 76, 77, 78,  0, 79
  79, 80, 81, 82, 83, 84, 85, 86, 87, 88, 89, 90, 91,  0
		

Crossrefs

Transpose: A285722.
Cf. A000217 (row 1), A000124 (column 1, from 1 onward).
Cf. also A285733.

Programs

  • Mathematica
    A[n_, n_] = 0;
    A[n_, k_] /; k == n - 1 := (k^2 - k + 2)/2;
    A[1, k_] := (k^2 - 3 k + 4)/2;
    A[n_, k_] /; 1 <= k <= n - 2 := A[n, k] = A[n, k + 1] + 1;
    A[n_, k_] /; k > n := A[n, k] = A[n - 1, k] + 1;
    T[n_, k_] := A[k, n];
    Table[T[n - k + 1, k], {n, 1, 14}, {k, n, 1, -1}] // Flatten (* Jean-François Alcover, Nov 19 2019 *)
  • Python
    def T(n, m): return ((n + m)**2 - n - 3*m + 2)//2
    def A(n, k): return 0 if n == k else T(n - k, k) if n>k else T(n, k - n)
    for n in range(1, 21): print([A(n - k + 1, k) for k in range(1, n + 1)]) # Indranil Ghosh, May 03 2017
  • Scheme
    (define (A285723 n) (A285722bi (A004736 n) (A002260 n))) ;; For A285722bi see A285722.
    

Formula

A(n,k) = A285722(k,n).