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a(n) = Product_{i=2..n} (prime(n+1)-prime(i)).
1

%I #4 Oct 01 2013 17:57:42

%S 1,6,40,1728,10560,604800,4386816,348364800,76859228160,490311843840,

%T 172454510592000,6951148594790400,54188395462656000,

%U 5673488083845120000,2112698895984230400000,458667310457770160947200

%N a(n) = Product_{i=2..n} (prime(n+1)-prime(i)).

%F (3-2)=1, (5-2)*(5-3)=6, (7-2)*(7-3)*(7-5)=40, ...

%o (PARI) fnpr(n)=forprime(x=3,n,pr=1; forprime(y=2,x-1,pr=pr*(x-y)); print1(pr","))

%K easy,nonn

%O 1,2

%A _Cino Hilliard_, Aug 05 2003