%I #6 Jul 31 2015 01:25:44
%S 6,20,56,36,11,13,680,3876,245157,34597290,84672315,12875774670,
%T 244662670200,800472431850,14833897694226,973469712824056,
%U 48402641245296107,191724747789809255,9989690752182277136
%N Let c = composite(n) & p = prime(n); a(n) = binomial( max(c,p), min(c,p) ).
%C 11 and 13 are the only prime terms. For a(7) onwards sequence is monotonically increasing.
%e a(3) = C(8,5) = 56, a(8) = C(19,15) =3876.
%t Composite[ n_Integer ] := Block[{k = n + PrimePi[ n ] + 1}, While[ k != n + PrimePi[ k ] + 1, k++ ]; k]; f[n_] := Block[{a = Sort[{Composite[n], Prime[n]}]}, Binomial[Last[a], First[a]]]; Table[ f[n], {n, 19}] (* _Robert G. Wilson v_, Jul 16 2005 *)
%K easy,nonn
%O 1,1
%A _Amarnath Murthy_, Jul 14 2005
%E More terms from _Robert G. Wilson v_, Jul 16 2005