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A011913 a(n) = floor(n*(n - 1)*(n - 2)/31).

%I A011913 #22 Oct 19 2024 21:40:03
%S A011913 0,0,0,0,0,1,3,6,10,16,23,31,42,55,70,88,108,131,157,187,220,257,298,
%T A011913 342,391,445,503,566,634,707,785,870,960,1056,1158,1266,1381,1503,
%U A011913 1632,1768,1912,2063,2221,2388,2563,2746,2938,3138,3347,3565,3793,4030,4277,4534,4800,5077,5365,5663,5972,6292,6623,6965,7320,7686,8064,8454,8856,9271,9699,10140,10594
%N A011913 a(n) = floor(n*(n - 1)*(n - 2)/31).
%H A011913 G. C. Greubel, <a href="/A011913/b011913.txt">Table of n, a(n) for n = 0..2000</a>
%H A011913 <a href="/index/Rec#order_34">Index entries for linear recurrences with constant coefficients</a>, signature (3,-3,1,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,1,-3,3,-1).
%F A011913 G.f.: x^5*(1 +x^4 -x^5 +2*x^7 -x^8 +x^10 -x^11 +x^12 +x^14 -x^15 +x^16 -x^18 +2*x^19 -x^21 +x^22 +2*x^26 -2*x^27 +x^28)/((1-x)^3*(1-x^31)). - _Peter J. C. Moses_, Jun 02 2014
%t A011913 Floor[6*Binomial[Range[0,80], 3]/31] (* _G. C. Greubel_, Oct 19 2024 *)
%o A011913 (PARI) a(n) = n*(n-1)*(n-2)\31 \\ _Jianing Song_, Oct 15 2018
%o A011913 (Magma) [Floor(6*Binomial(n,3)/31): n in [0..80]]; // _G. C. Greubel_, Oct 19 2024
%o A011913 (SageMath) [6*binomial(n,3)//31 for n in range(81)] # _G. C. Greubel_, Oct 19 2024
%Y A011913 Cf. A011886.
%K A011913 nonn
%O A011913 0,7
%A A011913 _N. J. A. Sloane_
%E A011913 More terms added by _G. C. Greubel_, Oct 19 2024