A128558 - OEIS

%I #10 Aug 18 2015 00:19:36

%S 1,2,4,6,6,8,8,8,12,12,24,12,24,32,16,20,40,36,24,48,24,64,32,40,48,

%T 60,48,64,48,64,32,56,48,56,64,36,72,48,128,80,64,80,160,64,72,96,48,

%U 48,60,108,72,96,192,64,64,160,128,80,160,64,128,64,256,96,168,128,256,256

%N a(n) = the number of positive divisors of (n!/A128557(n)!).

%C a(n) is >= n, for each positive integer n.

%p A128557 := proc(n) local A, k: A:={}: for k from 1 to n do if numtheory[tau](n!/k!)>=n then A:=A union {k} else A:=A fi od: A[nops(A)]; end: A128558 := proc(n) numtheory[tau]( n!/A128557(n)!) ; end: seq(A128558(n),n=1..80) ; # _R. J. Mathar_, Oct 09 2007

%Y Cf. A128557.

%K nonn

%O 1,2

%A _Leroy Quet_, Mar 10 2007

%E More terms from _R. J. Mathar_, Oct 09 2007