This site is supported by donations to The OEIS Foundation.

 Hints (Greetings from The On-Line Encyclopedia of Integer Sequences!)
 A007956 Product of proper divisors of n. 17

%I

%S 1,1,1,2,1,6,1,8,3,10,1,144,1,14,15,64,1,324,1,400,21,22,1,13824,5,26,

%T 27,784,1,27000,1,1024,33,34,35,279936,1,38,39,64000,1,74088,1,1936,

%U 2025,46,1,5308416,7,2500,51,2704,1,157464,55,175616,57,58,1,777600000,1,62,3969,32768,65

%N Product of proper divisors of n.

%H T. D. Noe, <a href="/A007956/b007956.txt">Table of n, a(n) for n=1..1000</a>

%F a(n) = A007955(n)/n = n^(A000005(n)/2-1) = sqrt(n^(number of factors of n other than 1 and n))

%F a(n) = product{A027751(n,k): k=1..A000005(n)-1). - _Reinhard Zumkeller_, Feb 04 2013

%p A007956 := n -> mul(i,i=op(numtheory[divisors](n) minus {1,n}));

%p seq(A007956(i), i=1..79); # - Peter Luschny, Mar 22 2011

%t Table[Times@@Most[Divisors[n]], {n, 65}] (* From Alonso del Arte, Apr 18 2011 *)

%o (PARI) A007956(n) = {local(a);a=1;fordiv(n,d,a=a*d);a/n} [From _Michael B. Porter_, Dec 01 2009]

%o a007956 = product . a027751_row

%o -- _Reinhard Zumkeller_, Feb 04 2013, Nov 02 2011

%Y Cf. A000005, A007955, A048671, A182936.

%K nonn,easy,nice

%O 1,4

%A R. Muller

%E More terms from Scott Lindhurst (ScottL(AT)alumni.princeton.edu)

Lookup | Welcome | Wiki | Register | Music | Plot 2 | Demos | Index | Browse | More | WebCam
Contribute new seq. or comment | Format | Transforms | Puzzles | Hot | Classics
Recent Additions | More pages | Superseeker | Maintained by The OEIS Foundation Inc.

Content is available under The OEIS End-User License Agreement .