A008308 Triangle of tangent numbers.

1, 1, 2, 1, 8, 1, 16, 20, 1, 136, 40, 1, 272, 616, 70, 1, 3968, 2016, 112, 1, 7936, 28160, 5376, 168, 1, 176896, 135680, 12432, 240, 1, 353792, 1805056, 508640, 25872, 330, 1, 11184128, 11977856, 1595264, 49632, 440, 1, 22368256, 154918400, 59835776

Offset: 1

Author

N. J. A. Sloane

Keywords

• tabf
• nonn
• nice

Examples

			Triangle begins:
    1;
    1;
    2,  1;
    8,  1;
   16, 20, 1;
  136, 40, 1;
  ...
		

References

• L. Comtet, Advanced Combinatorics, Reidel, 1974, p. 259.

Crossrefs

Essentially the same triangle as A059419, which is the main entry for this triangle.

Row sums give A006229.

Programs

Mathematica

T[n_, n_] = 1; T[n_, k_] /; 0 <= k <= n := T[n, k] = T[n - 1, k - 1] + k*(k + 1)*T[n - 1, k + 1]; T[, ] = 0;
row[n_] := DeleteCases[Table[T[n, k], {k, 1, n}] , 0];
Array[row, 13] // Flatten (* Jean-François Alcover, Nov 09 2017 *)

Extensions

More terms from Larry Reeves (larryr(AT)acm.org), Feb 08 2001