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A024174 a(n) is floor((4th elementary symmetric function of 1,2,..,n)/(3rd elementary symmetric function of 1,2,...,n)). 1
0, 0, 1, 2, 3, 4, 6, 8, 10, 13, 16, 19, 22, 25, 29, 33, 37, 42, 47, 52, 57, 62, 68, 74, 80, 87, 94, 101, 108, 115, 123, 131, 139, 148, 157, 166, 175, 184, 194, 204, 214, 225, 236, 247, 258, 269, 281, 293, 305, 318, 331, 344, 357, 370, 384, 398, 412, 427, 442 (list; graph; refs; listen; history; text; internal format)
OFFSET

3,4

LINKS

Ivan Neretin, Table of n, a(n) for n = 3..10000

FORMULA

Empirical g.f.: x^5*(x^7-2*x^6+2*x^5-2*x^4+x^3-x^2+x-1) / ((x-1)^3*(x^2+1)*(x^4+1)). - Colin Barker, Aug 16 2014

a(n) = floor( A000915(n-3)/A001303(n-2) ). - R. J. Mathar, Sep 23 2016

a(n) = floor((n - 3)(15n^3 + 15n^2 - 10n - 8)/(120n(n + 1))]. - Ivan Neretin, Nov 25 2016

EXAMPLE

G.f. = x^5 + 2*x^6 + 3*x^7 + 4*x^8 + 6*x^9 + 8*x^10 + 10*x^11 + 13*x^12 + ...

MATHEMATICA

Table[Floor[(n - 3) (15 n^3 + 15 n^2 - 10 n - 8)/(120 n (n + 1))], {n, 3, 45}] (* Ivan Neretin, Nov 25 2016 *)

PROG

(PARI) {a(n) = if( n<4, 0, (n-3) * (15*n^3 + 15*n^2 - 10*n - 8) \ (120 * n * (n+1)))}; /* Michael Somos, Nov 25 2016 */

CROSSREFS

Sequence in context: A100919 A184109 A214780 * A008739 A280706 A025695

Adjacent sequences:  A024171 A024172 A024173 * A024175 A024176 A024177

KEYWORD

nonn

AUTHOR

Clark Kimberling

EXTENSIONS

Offset set to 3 by R. J. Mathar, Sep 23 2016

STATUS

approved

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Last modified September 20 10:44 EDT 2019. Contains 327229 sequences. (Running on oeis4.)