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

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, 113, 122, 131, 141, 151, 161, 172, 183, 194, 205, 217, 229, 242, 255, 268, 282, 296, 310, 324

Offset

2,4

Links

Ivan Neretin, Table of n, a(n) for n = 2..10000

Formula

a(n) = floor( A001303(n-2)/A000914(n-1) ). - R. J. Mathar, Sep 15 2009

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

a(n) = floor((1/2)*(n - 2)*n*(n + 1)/(3*n + 2)).

Example

a(3) = floor(6/11) = 0; a(4) = floor(50/35) = 1. - R. J. Mathar, Sep 15 2009

Maple

seq(floor((1/2)*n*(n-2)*(n+1)/(3*n+2)), n=2..50); # Muniru A Asiru, May 19 2018

Mathematica

Table[Floor[1/2 (n - 2) n (n + 1)/ (3 n + 2)], {n, 2, 45}] (* Ivan Neretin, May 19 2018 *)

Prog

(GAP) List([2..50], n->Int((1/2)*n*(n-2)*(n+1)/(3*n+2))); # Muniru A Asiru, May 19 2018

Crossrefs

Sequence in context: A302648 A269746 A056827 * A233735 A085577 A331130

Adjacent sequences: A024169 A024170 A024171 * A024173 A024174 A024175

Keyword

nonn

Author

Clark Kimberling

Extensions

Offset set to 2 by R. J. Mathar, Sep 15 2009

Status

approved