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A117436 Triangle related to exp(x)sec(2x). 2
1, 0, 1, 4, 0, 1, 0, 12, 0, 1, 80, 0, 24, 0, 1, 0, 400, 0, 40, 0, 1, 3904, 0, 1200, 0, 60, 0, 1, 0, 27328, 0, 2800, 0, 84, 0, 1, 354560, 0, 109312, 0, 5600, 0, 112, 0, 1, 0, 3191040, 0, 327936, 0, 10080, 0, 144, 0, 1, 51733504, 0, 15955200, 0, 819840, 0, 16800, 0, 180, 0 (list; table; graph; refs; listen; history; text; internal format)
OFFSET

0,4

COMMENTS

Row sums are A117437. Inverse is A117435. First column is A002436.

Conjecture: The d-th diagonal (starting with d=0) is proportional to the sequence of generalized binomial coefficients binom(-x, d) where x is the column index. - Søren G. Have, Feb 26 2017

LINKS

Table of n, a(n) for n=0..64.

FORMULA

Number triangle whose k-th column has e.g.f. (x^k/k!)*sec(2x).

EXAMPLE

1,

0, 1,

4, 0, 1,

0, 12, 0, 1,

80, 0, 24, 0, 1,

0, 400, 0, 40, 0, 1,

3904, 0, 1200, 0, 60, 0, 1,

0, 27328, 0, 2800, 0, 84, 0, 1,

354560, 0, 109312, 0, 5600, 0, 112, 0, 1,

0, 3191040, 0, 327936, 0, 10080, 0, 144, 0, 1,

51733504, 0, 15955200, 0, 819840, 0, 16800, 0, 180, 0, 1

CROSSREFS

Cf. A002436, A117435, A117437.

Sequence in context: A117435 A282252 A268367 * A136448 A166318 A166317

Adjacent sequences:  A117433 A117434 A117435 * A117437 A117438 A117439

KEYWORD

nonn,tabl

AUTHOR

Paul Barry, Mar 16 2006

STATUS

approved

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Last modified December 14 21:25 EST 2017. Contains 296020 sequences.