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Denominators of coefficients in expansion of 1/(cos x - sin x).
2

%I #4 Dec 12 2016 09:16:31

%S 1,1,2,6,8,120,80,5040,13440,362880,1209600,39916800,53222400,

%T 566092800,29059430400,1307674368000,6974263296000,355687428096000,

%U 237124952064000,121645100408832000,73724303278080000,51090942171709440000,19719311013642240000

%N Denominators of coefficients in expansion of 1/(cos x - sin x).

%H Clark Kimberling, <a href="/A279258/b279258.txt">Table of n, a(n) for n = 0..1000</a>

%e 1/1 + (1/1)x + (3/2)x^2 + (11/6)x^3 + (19/8)x^3 + ... ; 1/1, 1/1, 3/2, 11/6, ... = A279257/A279258.

%t z = 30; t = CoefficientList[Series[1/(Cos[x] - Sin[x]), {x, 0, z}], x];

%t Numerator[t] (* A279257 *)

%t Denominator[t] (* A279258 *)

%Y Cf. A279257.

%K nonn,easy,frac

%O 0,3

%A _Clark Kimberling_, Dec 11 2016