A001007 - OEIS

%I #13 Jan 21 2013 14:03:47

%S 1,2,15,42,421,1331,15119,618765,2155578,98032875,1290154807,

%T 4682196239,63117678751,3186252107917,164886529617695,616630679090258,

%U 32763760653353135,467443761039641135,1768227793278781667,96699391743949360451,1402535447576150395335

%N a(n) = ( Sum C(p,i); i=1,...,floor(2p/3) ) / p^2, where p = prime(n).

%H T. D. Noe, <a href="/A001007/b001007.txt">Table of n, a(n) for n = 3..200</a>

%t Table[p = Prime[n]; Sum[Binomial[p, i], {i, 1, Floor[2*p/3]}]/p^2, {n, 3, 30}] (* _T. D. Noe_, Jan 21 2013 *)

%K nonn

%O 3,2

%A _R. K. Guy_