OFFSET
0,4
LINKS
Index entries for linear recurrences with constant coefficients, signature (7,-21,35,-35,21,-7,1)
FORMULA
a(n) = n*(n-1)*(n-2)*(n^3-9*n^2+32*n-38)/12.
G.f.: -2*x^3*(1+3*x+6*x^2+20*x^3)/(x-1)^7 . - R. J. Mathar, Feb 23 2017
a(n) = 2*A249460(n). - R. J. Mathar, Feb 23 2017
EXAMPLE
For n = 3 we get a(3) = 2 distinct ways to color the edges of a tetrahedron with three colors so that no two adjacent edges have the same color.
MATHEMATICA
Table[n (n - 1) (n - 2) (n^3 - 9 n^2 + 32 n - 38)/12, {n, 0, 34}]
PROG
(PARI) a(n) = n*(n-1)*(n-2)*(n^3-9*n^2+32*n-38)/12 \\ Charles R Greathouse IV, Feb 22 2017
CROSSREFS
KEYWORD
nonn,easy
AUTHOR
David Nacin, Feb 22 2017
STATUS
approved