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A008308 Triangle of tangent numbers. 1
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 (list; graph; refs; listen; history; text; internal format)
OFFSET
1,3
REFERENCES
L. Comtet, Advanced Combinatorics, Reidel, 1974, p. 259.
LINKS
EXAMPLE
Triangle begins:
1;
1;
2, 1;
8, 1;
16, 20, 1;
136, 40, 1;
...
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 *)
CROSSREFS
Essentially the same triangle as A059419, which is the main entry for this triangle.
Row sums give A006229.
Sequence in context: A369779 A125911 A009385 * A176889 A208753 A118931
KEYWORD
tabf,nonn,nice
AUTHOR
EXTENSIONS
More terms from Larry Reeves (larryr(AT)acm.org), Feb 08 2001
STATUS
approved

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Last modified March 29 10:22 EDT 2024. Contains 371268 sequences. (Running on oeis4.)