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A188669
a(n) = ceiling(binomial(2*n-1,n-1)/n).
1
1, 2, 4, 9, 26, 77, 246, 805, 2702, 9238, 32066, 112674, 400024, 1432736, 5170584, 18783763, 68635478, 252087092, 930138522, 3446163221, 12815663678, 47820430994, 178987624514, 671825076732, 2528212128756, 9536894864387, 36054433808299, 136583760727865, 518401146543812, 1971076359414358, 7506908923471954, 28634752202227978
OFFSET
1,2
COMMENTS
A useful lower bound when studying certain problems involving compositions.
LINKS
MATHEMATICA
Table[Ceiling[Binomial[2 n - 1, n - 1]/n], {n, 35}] (* Harvey P. Dale, Apr. 09 2011 *)
PROG
(Magma) [Ceiling(Binomial(2*n-1, n-1)/n): n in [1..60]]; // Vincenzo Librandi, Sep 07 2016
CROSSREFS
See A201058, A201059 for numerators and denominators without ceiling. - F. Chapoton, Aug 15 2021
Sequence in context: A125799 A220880 A307317 * A243568 A087378 A004252
KEYWORD
nonn
AUTHOR
Robert Gerbicz and N. J. A. Sloane, Apr 07 2011
STATUS
approved