login
A145565
Denominators of partial sums of a certain series of inverse central binomial coefficients.
1
1, 4, 36, 720, 25200, 10800, 5821200, 302702400, 908107200, 15437822400, 3226504881600, 248192683200, 964724959598400, 964724959598400, 1607874932664000, 186513492189024000, 98292610383615648000, 1605505432763232000, 16808036375598275808000, 124379469179427240979200
OFFSET
0,2
COMMENTS
See A145564 for the numerators, a reference and a W. Lang link.
FORMULA
a(n)=denominator(r(n)), with the rationals (in lowest terms) r(n):=sum(1/(binomial(2*k,k)*(k+1)),k=0..n).
EXAMPLE
Rationals r(n) (in lowest terms):[1, 5/4, 47/36, 949/720, 33287/25200, 14273/10800, 7694047/5821200,...].
CROSSREFS
Cf. A145564.
Sequence in context: A156630 A289545 A322782 * A360903 A214669 A126152
KEYWORD
nonn,frac,easy
AUTHOR
Wolfdieter Lang, Oct 17 2008
STATUS
approved