

A085539


a(n) = n^6  n^5.


6



0, 0, 32, 486, 3072, 12500, 38880, 100842, 229376, 472392, 900000, 1610510, 2737152, 4455516, 6991712, 10631250, 15728640, 22717712, 32122656, 44569782, 60800000, 81682020, 108226272, 141599546, 183140352, 234375000, 297034400, 373071582, 464679936
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OFFSET

0,3


COMMENTS

For n>=1, a(n) is equal to the number of functions f:{1,2,3,4,5,6}>{1,2,...,n} such that for a fixed x in {1,2,3,4,5,6} and a fixed y in {1,2,...,n} we have f(x)<>y.  Aleksandar M. Janjic and Milan Janjic, Mar 13 2007


LINKS



FORMULA

G.f.: 2*x^2*(x^4+41*x^3+171*x^2+131*x+16)/(x1)^7.  Colin Barker, Nov 06 2012
Sum_{n>=2} 1/a(n) = 5  Sum_{k=2..5} zeta(k).  Amiram Eldar, Jul 05 2020


MATHEMATICA



PROG



CROSSREFS



KEYWORD

nonn,easy


AUTHOR



STATUS

approved



