A110378 a(n) = Sum_{prime p <= n} n!/p!.

1, 4, 16, 81, 486, 3403, 27224, 245016, 2450160, 26951761, 323421132, 4204474717, 58862646038, 882939690570, 14127035049120, 240159595835041, 4322872725030738, 82134581775584023, 1642691635511680460

Offset: 2

Author

Amarnath Murthy, Jul 24 2005

Keywords

• easy
• nonn

Examples

			a(6) = 6!(2! + 1/3! + 1/5!) = 486.
		

Crossrefs

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

Programs

Maple

a:=proc(n) local s, i: s:=0: for i from 2 to n do if isprime(i)=true then s:=s+1/i! else s:=s: fi: od: n!*s: end: seq(a(n),n=2..23); # Emeric Deutsch, Jul 24 2005

Extensions

Corrected and extended by Emeric Deutsch, Jul 24 2005