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A007956
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Product of proper divisors of n.
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17
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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, 27, 784, 1, 27000, 1, 1024, 33, 34, 35, 279936, 1, 38, 39, 64000, 1, 74088, 1, 1936, 2025, 46, 1, 5308416, 7, 2500, 51, 2704, 1, 157464, 55, 175616, 57, 58, 1, 777600000, 1, 62, 3969, 32768, 65
(list; graph; refs; listen; history; internal format)
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OFFSET
| 1,4
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LINKS
| T. D. Noe, Table of n, a(n) for n=1..1000
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FORMULA
| a(n) = A007955(n)/n = n^(A000005(n)/2-1) = sqrt(n^(number of factors of n other than 1 and n))
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MAPLE
| A007956 := n -> mul(i, i=op(numtheory[divisors](n) minus {1, n}));
seq(A007956(i), i=1..79); # - Peter Luschny, Mar 22 2011
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MATHEMATICA
| Table[Times@@Most[Divisors[n]], {n, 65}] (* From Alonso del Arte, Apr 18 2011 *)
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PROG
| (PARI) A007956(n) = {local(a); a=1; fordiv(n, d, a=a*d); a/n} [From Michael Porter (michael_b_porter(AT)yahoo.com), Dec 01 2009]
(Haskell)
a007956 n = product [d | d <- [1..n-1], mod n d == 0]
-- Reinhard Zumkeller, Nov 02 2011
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CROSSREFS
| Cf. A000005, A007955, A048671, A182936.
Sequence in context: A088123 A050932 A166120 * A107754 A181569 A191093
Adjacent sequences: A007953 A007954 A007955 * A007957 A007958 A007959
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KEYWORD
| nonn,easy,nice
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AUTHOR
| R. Muller
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EXTENSIONS
| More terms from Scott Lindhurst (ScottL(AT)alumni.princeton.edu)
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