A279435 Denominators of coefficients in expansion of 1/(1 + e^x - e^(2x)).

1, 1, 2, 6, 24, 120, 144, 5040, 40320, 362880, 725760, 39916800, 479001600, 6227020800, 17435658240, 1307674368000, 20922789888000, 355687428096000, 1280474741145600, 850665037824000, 221172909834240000

Offset

0,3

Links

Clark Kimberling, Table of n, a(n) for n = 0..1000

Example

(1/1) + (1/1)x + (5/2)x^2 + (31/6)x^3 + ... ; 1/1, 1/1, 5/2, 31/6, ... = A279434/A279435.

Mathematica

z = 20; t = CoefficientList[Series[1/(1 + E^x - E^(2 x)), {x, 0, z}], x]
Numerator[t]   (* A279434 *)
Denominator[t] (* A279435 *)

Crossrefs

Cf. A279434.

Sequence in context: A319206 A190393 A263709 * A263699 A083267 A130480

Adjacent sequences: A279432 A279433 A279434 * A279436 A279437 A279438

Keyword

nonn,easy,frac

Author

Clark Kimberling, Dec 12 2016

Status

approved