cp's OEIS Frontend

A024172 Integer part of ((3rd elementary symmetric function of 1,2,..,n)/(2nd elementary symmetric function of 1,2,...,n)).

%I A024172 #22 May 28 2018 09:17:30
%S A024172 0,0,1,2,4,6,8,10,13,16,20,24,28,33,38,43,48,54,60,67,74,81,89,97,105,
%T A024172 113,122,131,141,151,161,172,183,194,205,217,229,242,255,268,282,296,
%U A024172 310,324
%N A024172 Integer part of ((3rd elementary symmetric function of 1,2,..,n)/(2nd elementary symmetric function of 1,2,...,n)).
%H A024172 Ivan Neretin, <a href="/A024172/b024172.txt">Table of n, a(n) for n = 2..10000</a>
%F A024172 a(n) = floor( A001303(n-2)/A000914(n-1) ). - _R. J. Mathar_, Sep 15 2009
%F A024172 Empirical g.f.: x^4*(x^4-x^3+x^2-x+1)*(x^5-x^3-x^2-x-1) / ((x-1)^3*(x^2+x+1)*(x^6+x^3+1)). - _Colin Barker_, Aug 16 2014
%F A024172 a(n) = floor((1/2)*(n - 2)*n*(n + 1)/(3*n + 2)).
%e A024172 a(3) = floor(6/11) = 0; a(4) = floor(50/35) = 1. - _R. J. Mathar_, Sep 15 2009
%p A024172 seq(floor((1/2)*n*(n-2)*(n+1)/(3*n+2)),n=2..50); # _Muniru A Asiru_, May 19 2018
%t A024172 Table[Floor[1/2 (n - 2) n (n + 1)/ (3 n + 2)], {n, 2, 45}] (* _Ivan Neretin_, May 19 2018 *)
%o A024172 (GAP) List([2..50],n->Int((1/2)*n*(n-2)*(n+1)/(3*n+2))); # _Muniru A Asiru_, May 19 2018
%K A024172 nonn
%O A024172 2,4
%A A024172 _Clark Kimberling_
%E A024172 Offset set to 2 by _R. J. Mathar_, Sep 15 2009