|
Search: id:A020477
|
|
|
| A020477 |
|
Sum of divisors of n is a cube. |
|
+0
12
|
|
| 1, 7, 102, 110, 142, 159, 187, 381, 690, 714, 770, 994, 1034, 1054, 1065, 1113, 1164, 1173, 1265, 1293, 1309, 1633, 1643, 2667, 3638, 3937, 4505, 4830, 4855, 5373, 5671, 5730, 5997, 6486, 6517, 6906, 7130, 7238, 7378, 7455, 7755, 7905, 8148, 8211, 8426
(list; graph; listen)
|
|
|
OFFSET
|
1,2
|
|
|
REFERENCES
|
David Wells, Curious and Interesting Numbers (Revised), Penguin Books, page 118.
|
|
LINKS
|
T. D. Noe, Table of n, a(n) for n=1..1000
|
|
EXAMPLE
|
Factor 381; divisors are 1, 3, 127, 381. Sum is 512. Integral cube root of n is 8. So 381 is in sequence.
|
|
MATHEMATICA
|
Do[If[IntegerQ[DivisorSigma[1, n]^(1/3)], Print[n]], {n, 1, 10^4}]
|
|
CROSSREFS
|
Cf. A006532.
Sequence in context: A001594 A052752 A142358 this_sequence A140633 A142400 A032460
Adjacent sequences: A020474 A020475 A020476 this_sequence A020478 A020479 A020480
|
|
KEYWORD
|
nonn
|
|
AUTHOR
|
David W. Wilson (davidwwilson(AT)comcast.net)
|
|
|
Search completed in 0.002 seconds
|
