|
|
A279110
|
|
Denominators of coefficients in expansion of 2/(1 + cos(sqrt(x))).
|
|
2
|
|
|
1, 4, 24, 2880, 40320, 7257600, 479001600, 697426329600, 20922789888000, 12804747411456000, 2432902008176640000, 264470759477084160000, 620448401733239439360000, 806582922253211271168000000, 304888344611713860501504000000, 4244045756995056938180935680000000
(list;
graph;
refs;
listen;
history;
text;
internal format)
|
|
|
OFFSET
|
0,2
|
|
LINKS
|
|
|
FORMULA
|
|
|
EXAMPLE
|
1/1 + (1/4)x + (1/24)x^2 + (17/2880)x^3 + ... ; 1/1, 1/4, 1/24, 17/2880, 31/40320, ... = |A089171|/A279110.
|
|
MATHEMATICA
|
z = 26; t = CoefficientList[Series[2/(1 + Cos[Sqrt[x]]), {x, 0, z}], x];
Numerator[t] (* A089171, unsigned *)
|
|
CROSSREFS
|
|
|
KEYWORD
|
nonn,easy,frac
|
|
AUTHOR
|
|
|
STATUS
|
approved
|
|
|
|