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A024197
a(n) = 3rd elementary symmetric function of the first n+2 odd positive integers.
4
15, 176, 950, 3480, 10045, 24640, 53676, 106800, 197835, 345840, 576290, 922376, 1426425, 2141440, 3132760, 4479840, 6278151, 8641200, 11702670, 15618680, 20570165, 26765376, 34442500, 43872400, 55361475, 69254640, 85938426, 105844200, 129451505
OFFSET
1,1
FORMULA
a(n) = n*(n+1)*(n+2)^2*(n^2+3*n+1)/6.
G.f.: -x*(x^3+33*x^2+71*x+15) / (x-1)^7. - Colin Barker, Aug 15 2014
a(n) = A004320(n)*A028387(n). - R. J. Mathar, Oct 01 2016
a(n) = A028338(n+2, n-1), n >= 1, (fourth diagonal). See a crossref. below. - Wolfdieter Lang, Jul 21 2017
PROG
(PARI) Vec(-x*(x^3+33*x^2+71*x+15)/(x-1)^7 + O(x^100)) \\ Colin Barker, Aug 15 2014
CROSSREFS
Contribution from Johannes W. Meijer, Jun 08 2009: (Start)
Equals fourth right hand column of A028338 triangle.
Equals fourth left hand column of A109692 triangle.
Equals fourth right hand column of A161198 triangle divided by 2^m.
(End)
Sequence in context: A069379 A184285 A120995 * A210782 A071535 A081043
KEYWORD
nonn,easy
STATUS
approved