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a(n) = floor(C(n+6,6)/C(n+2,2)).
5

%I #12 Mar 24 2023 06:15:18

%S 1,2,4,8,14,22,33,47,66,91,121,158,204,258,323,399,487,590,708,843,

%T 996,1170,1365,1583,1827,2097,2397,2728,3091,3490,3927,4403,4921,5483,

%U 6092,6751,7462,8227,9050,9933,10879,11891,12972,14125,15353,16660,18048

%N a(n) = floor(C(n+6,6)/C(n+2,2)).

%H Vincenzo Librandi, <a href="/A084626/b084626.txt">Table of n, a(n) for n = 0..1000</a>

%F a(n) = 1 + floor( n*(n+9)*(n^2 +9*n +38)/360 ).

%F a(n) = floor(binomial(n+6,4)/15). - _G. C. Greubel_, Mar 24 2023

%t Table[Floor[n*(n+9)*(n^2+9*n+38)/360] +1, {n,0,50}] (* _Vincenzo Librandi_, Aug 02 2013 *)

%t Floor[Binomial[Range[6,76],4]/15] (* _G. C. Greubel_, Mar 24 2023 *)

%o (Magma) [Floor(n*(n+9)*(n^2+9*n+38)/360)+1: n in [0..50]]; // _Vincenzo Librandi_, Aug 02 2013

%o (SageMath) [binomial(n+6,4)//15 for n in range(71)] # _G. C. Greubel_, Mar 24 2023

%Y Cf. A011865, A084624, A084627, A084628, A084630, A084631.

%K nonn,easy

%O 0,2

%A _Paul Barry_, Jun 01 2003