A110379 a(n) = Sum_{composite c <= n} n!/c!.

1, 5, 31, 217, 1737, 15634, 156341, 1719751, 20637013, 268281169, 3755936367, 56339045506, 901424728097, 15324220377649, 275835966797683, 5240883369155977, 104817667383119541, 2201171015045510362

Offset: 4

Author

Amarnath Murthy, Jul 24 2005

Keywords

• easy
• nonn

Examples

			a(6) = 6!(1/4! + 1/6!) = 31.
		

Crossrefs

Cf. A038048, A110373, A110374, A110376, A110377, A110378.

Programs

Maple

a:=proc(n) local s,i :s:=0: for i from 4 to n do if isprime(i)=false then s:=s+1/i! else s:=s: fi od: n!*s; end; seq(a(n),n=4..24); # Emeric Deutsch, Jul 25 2005

Extensions

More terms from Emeric Deutsch, Jul 25 2005