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A020477
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Sum of divisors of n is a cube.
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14
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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; refs; listen; history; internal format)
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OFFSET
| 1,2
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REFERENCES
| David Wells, Curious and Interesting Numbers (Revised), Penguin Books, page 118.
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LINKS
| T. D. Noe, Table of n, a(n) for n=1..1000
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EXAMPLE
| Factor 381; divisors are 1, 3, 127, 381. Sum is 512. Integral cube root of n is 8. So 381 is in sequence.
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MATHEMATICA
| Do[If[IntegerQ[DivisorSigma[1, n]^(1/3)], Print[n]], {n, 1, 10^4}]
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CROSSREFS
| Cf. A006532.
Sequence in context: A165878 A175345 A142358 * A203356 A140633 A142400
Adjacent sequences: A020474 A020475 A020476 * A020478 A020479 A020480
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KEYWORD
| nonn
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AUTHOR
| David W. Wilson (davidwwilson(AT)comcast.net)
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