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.

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A116853 Difference triangle of factorial numbers read by upward diagonals.

Original entry on oeis.org

1, 1, 2, 3, 4, 6, 11, 14, 18, 24, 53, 64, 78, 96, 120, 309, 362, 426, 504, 600, 720, 2119, 2428, 2790, 3216, 3720, 4320, 5040, 16687, 18806, 21234, 24024, 27240, 30960, 35280, 40320
Offset: 1

Views

Author

Gary W. Adamson, Feb 24 2006

Keywords

Comments

This is a subsequence of Euler's difference table A068106 and of A047920 (in a different ordering), since 0! = 1 was left out here. - Georg Fischer, Mar 23 2019

Examples

			Starting with 1, 2, 6, 24, 120 ... we take the first difference row (A001563), second, third, etc. Reorient into a flush left format, getting:
[1]    1;
[2]    1,   2;
[3]    3,   4,   6;
[4]   11,  14,  18,  24;
[5]   53,  64,  78,  96, 120;
[6]  309, 362, 426, 504, 600, 720;
...
		

Crossrefs

Cf. A000142 (factorial numbers).
Cf. A000255 (first column and inverse binomial transform of A000142).
N-th forward differences of A000142: A001563 (1st), A001564 (2nd), A001565 (3rd), A001688 (4th), A001689 (5th).
Cf. A047920 (with 0!, different order), A068106 (with 0!), A180191 (row sums), A246606 (central terms).

Programs

  • Haskell
    a116853 n k = a116853_tabl !! (n-1) !! (k-1)
    a116853_row n = a116853_tabl !! (n-1)
    a116853_tabl = map reverse $ f (tail a000142_list) [] where
       f (u:us) vs = ws : f us ws where ws = scanl (-) u vs
    -- Reinhard Zumkeller, Aug 31 2014
  • Mathematica
    rows = 8;
    rr = Range[rows]!;
    dd = Table[Differences[rr, n], {n, 0, rows-1}];
    T = Array[t, {rows, rows}];
    Do[Thread[Evaluate[Diagonal[T, -k+1]] = dd[[k, ;;rows-k+1]]], {k, rows}];
    Table[t[n, k], {n, 1, rows}, {k, 1, n}] // Flatten (* Jean-François Alcover, Dec 21 2019 *)

Formula

Take successive difference rows of factorial numbers n! starting with n=1. Reorient into a triangle format.
Previous Showing 11-11 of 11 results.