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a(n) = floor( binomial(n,9)/10 ).
2

%I #17 Sep 08 2022 08:44:37

%S 0,0,0,0,0,0,0,0,0,0,1,5,22,71,200,500,1144,2431,4862,9237,16796,

%T 29393,49742,81719,130750,204297,312455,468682,690690,1001500,1430715,

%U 2016007,2804880,3856710,5245125,7060746

%N a(n) = floor( binomial(n,9)/10 ).

%H Vincenzo Librandi, <a href="/A011846/b011846.txt">Table of n, a(n) for n = 0..1000</a>

%F a(n) = floor( binomial(n+1,10)/(n+1)). [_Gary Detlefs_, Nov 23 2011]

%p A011846:=n->floor(binomial(n,9)/10): seq(A011846(n), n=0..60); # _Wesley Ivan Hurt_, Apr 10 2017

%t Table[Floor[Binomial[n, 9]/10], {n, 0, 50}] (* _Vincenzo Librandi_, Apr 11 2017 *)

%o (Magma) [Floor(Binomial(n,9)/10): n in [0..50]]; // _Vincenzo Librandi_, Apr 11 2017

%Y A column of triangle A011847.

%K nonn,easy

%O 0,12

%A _N. J. A. Sloane_