|
Search: id:A048741
|
|
|
| A048741 |
|
Product of aliquot divisors of composite n (1 and primes omitted). |
|
+0
4
|
|
| 2, 6, 8, 3, 10, 144, 14, 15, 64, 324, 400, 21, 22, 13824, 5, 26, 27, 784, 27000, 1024, 33, 34, 35, 279936, 38, 39, 64000, 74088, 1936, 2025, 46, 5308416, 2500, 51, 2704, 157464, 55, 175616, 57, 58, 777600000, 62, 3969, 32768, 65, 287496, 4624, 69
(list; graph; listen)
|
|
|
OFFSET
|
1,1
|
|
|
REFERENCES
|
Albert H. Beiler, Recreations in the Theory of Numbers, 2nd ed., pages 10, 23. New York: Dover, 1966. ISBN 0-486-21096-0.
|
|
EXAMPLE
|
The third composite number is 8, for which the product of aliquot divisors is 4*2*1 = 8, so a(3)=8.
|
|
MATHEMATICA
|
Composite[n_] := FixedPoint[n + PrimePi[ # ] + 1 &, n + PrimePi[n] + 1]; Table[ Times @@ Select[ Divisors[ Composite[n]], # < Composite[n] & ], {n, 1, 60} ]
|
|
CROSSREFS
|
This is A007956 omitting the 1's.
Cf. A007422, A007956, A048740.
Sequence in context: A019786 A067067 A119279 this_sequence A115317 A117932 A073411
Adjacent sequences: A048738 A048739 A048740 this_sequence A048742 A048743 A048744
|
|
KEYWORD
|
easy,nonn
|
|
AUTHOR
|
Enoch Haga (Enokh(AT)comcast.net)
|
|
|
Search completed in 0.002 seconds
|
