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a(n) = ceiling(binomial(n,9)/n).
3

%I #18 Sep 08 2022 08:45:00

%S 0,0,0,0,0,0,0,0,1,1,5,19,55,143,334,715,1430,2702,4862,8398,13997,

%T 22610,35530,54480,81719,120175,173587,246675,345345,476905,650325,

%U 876525,1168700,1542684,2017356,2615092,3362260,4289780,5433722

%N a(n) = ceiling(binomial(n,9)/n).

%H G. C. Greubel, <a href="/A053733/b053733.txt">Table of n, a(n) for n = 1..1000</a>

%H R. L. Graham and N. J. A. Sloane, <a href="http://dx.doi.org/10.1109/TIT.1980.1056141">Lower bounds for constant weight codes</a>, IEEE Trans. Inform. Theory, 26 (1980), 37-43.

%p seq(ceil(binomial(n,9)/n), n=1..40); # _G. C. Greubel_, Sep 06 2019

%t Table[Ceiling[Binomial[n, 9]/n], {n, 40}] (* _G. C. Greubel_, Sep 06 2019 *)

%o (PARI) vector(40, n, ceil(binomial(n,9)/n)) \\ _G. C. Greubel_, Sep 06 2019

%o (Magma) [Ceiling(Binomial(n,9)/n): n in [1..40]]; // _G. C. Greubel_, Sep 06 2019

%o (Sage) [ceil(binomial(n,9)/n) for n in (1..40)] # _G. C. Greubel_, Sep 06 2019

%Y Cf. Sequences of the form ceiling(binomial(n,k)/n): A000012 (k=1), A004526 (k=2), A007997 (k=3), A008646 (k=5), A032192 (k=7), A053618 (k=4), A053643 (k=6), A053731 (k=8), this sequence (k=9).

%K nonn

%O 1,11

%A _N. J. A. Sloane_, Mar 25 2000