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.

A053203 Pascal's triangle (excluding first, last three elements of each row) read by rows, row n read mod n.

Original entry on oeis.org

2, 0, 0, 0, 6, 0, 3, 0, 0, 3, 0, 0, 2, 0, 0, 0, 0, 0, 0, 0, 0, 4, 3, 0, 0, 0, 3, 4, 0, 0, 0, 0, 0, 0, 0, 0, 0, 7, 0, 7, 2, 7, 0, 7, 0, 5, 0, 3, 10, 0, 0, 10, 3, 0, 5, 0, 12, 0, 8, 0, 6, 0, 8, 0, 12, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 6, 0, 0, 6, 0, 0, 2, 0, 0, 6, 0, 0, 6, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0
Offset: 6

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Author

Asher Auel, Dec 12 1999

Keywords

Comments

Prime numbered rows contain all zeros.

Examples

			Triangle begins:
  2;
  0,0;
  0,6,0;
  3,0,0,3;
  0,0,2,0,0;
  ...
row 9 = 84 mod 9, 126 mod 9, 126 mod 9, 84 mod 9, = 3, 0, 0, 3.
		

Crossrefs

Row sums give A053206.
Cf. A053200, A053201, A053203, A007318 (Pascal's triangle).

Programs

  • Haskell
    a053203 n k = a053203_tabl !! (n - 6) !! k
    a053203_row n = a053203_tabl !! (n - 6)
    a053203_tabl = zipWith (\k row -> take (k - 5) $ drop 3 row)
                           [6..] $ drop 6 a053200_tabl
    -- Reinhard Zumkeller, Jan 24 2014
  • Mathematica
    Table[Mod[Binomial[n, k], n], {n, 6, 20}, {k, 3, n-3}] // Flatten (* Jean-François Alcover, Jan 17 2014 *)

Extensions

a(30) corrected by T. D. Noe, Feb 08 2008