A024193 Integer part of (3rd elementary symmetric function of S(n))/(2nd elementary symmetric of S(n)), where S(n) = {3,4, ..., n+4}.

1, 2, 4, 7, 9, 12, 15, 19, 23, 27, 32, 36, 42, 47, 53, 59, 66, 73, 80, 88, 95, 104, 112, 121, 130, 140, 150, 160, 171, 182, 193, 204, 216, 228, 241, 254, 267, 281, 295, 309, 323, 338, 353

Offset

1,2

Links

Ivan Neretin, Table of n, a(n) for n = 1..10000

Formula

a(n) = floor(A024184(n)/A024183(n+1)). - R. J. Mathar, Sep 23 2016

a(n) = floor(1/2 n (7 + n) (46 + 13 n + n^2)/(144 + 41 n + 3 n^2)). - Ivan Neretin, May 17 2018

Example

For n=2, the 3rd elementary symmetric function of (3,4,5,6) is 3*4*5 + 3*4*6 + 3*5*6 + 4*5*6 = 342, and the 2nd elementary symmetric function of (3,4,5,6) is 3*4 + 3*5 + 3*6 + 4*5 + 4*6 + 5*6 = 119.  So 342/119 = 2.8739..., and a(2) = 2. - Michael B. Porter, May 05 2018

Mathematica

Table[Floor[1/2 x (7 + x) (46 + 13 x + x^2)/(144 + 41 x + 3 x^2)], {x, 43}] (* Ivan Neretin, May 02 2018 *)

Crossrefs

Cf. A024184, A024183.

Sequence in context: A031435 A065560 A134886 * A064550 A186357 A212988

Adjacent sequences: A024190 A024191 A024192 * A024194 A024195 A024196

Keyword

nonn

Author

Clark Kimberling

Status

approved