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.

A219605 Square array T(n,k), read by antidiagonals: T(n,2*k) = T(n,2*k-1)*n, T(n,2*k+1) = T(n,2*k)+n, T(n,0) = 1.

Original entry on oeis.org

1, 1, 1, 0, 2, 1, 0, 2, 3, 1, 0, 3, 6, 4, 1, 0, 3, 8, 12, 5, 1, 0, 4, 16, 15, 20, 6, 1, 0, 4, 18, 45, 24, 30, 7, 1, 0, 5, 36, 48, 96, 35, 42, 8, 1, 0, 5, 38, 144, 100, 175, 48, 56, 9, 1, 0, 6, 76, 147, 400, 180, 288, 63, 72, 10, 1, 0, 6, 78, 441, 404, 900, 294, 441
Offset: 0

Views

Author

Philippe Deléham, Apr 12 2013

Keywords

Examples

			Square array begins:
1..1....0....0....0....0....0....0.....0.....0...
1..2....2....3....3....4....4....5.....5.....5...
1..3....6....8...16...18...36...38....76....78...
1..4...12...15...45...48..144..147...441...444...
1..5...20...24...96..100..400..404..1616..1620...
1..6...30...35..175..180..900..905..4525..4530...
1..7...42...48..288..294.1764.1770.10620.10626...
1..8...56...63..441..448.3136.3143.22001.22008...
1..9...72...80..640..648.5184.5192.41536.41544...
1.10...90...99..891..900.8100.8109.72971.72980...
...
		

Programs

  • Mathematica
    t[n_, k_] /; n < 0 || k < 0 = 0; t[n_, 0] = 1; t[n_, 1] = n+1; t[0, k_ /; k > 1] = 0; t[n_?Positive, k_?EvenQ] := t[n, k] = t[n, k-1]*n; t[n_?Positive, k_?OddQ] := t[n, k] = t[n, k-1] + n; Table[t[n-k, k], {n, 0, 11}, {k, n, 0, -1}] // Flatten (* Jean-François Alcover, Apr 19 2013 *)

Formula

T(n,0) = A000012(n).
T(n,1) = A000027(n).
T(n,2) = A002378(n+1).
T(n,3) = A005563(n).
T(n,4) = A152618(n+1).
T(n,5) = A045991(n+1).
T(n,6) = A035287(n+1).
T(0,k) = A019590(k+1).
T(1,k) = A008619(k+1).
T(2,k) = A123208(k).