

A194948


Numbers n such that sum of aliquot divisors of n, sigma(n)  n, is a cube.


3



1, 2, 3, 5, 7, 10, 11, 13, 17, 19, 23, 29, 31, 37, 41, 43, 47, 49, 53, 56, 59, 61, 67, 69, 71, 73, 76, 79, 83, 89, 97, 101, 103, 107, 109, 113, 122, 127, 131, 133, 137, 139, 149, 151, 157, 163, 167, 173, 179, 181, 191, 193, 197, 199, 211, 223, 227, 229, 233
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OFFSET

1,2


COMMENTS

For prime numbers, the sum of their aliquot divisors is exactly 1 = 1^3.


LINKS

Harvey P. Dale, Table of n, a(n) for n = 1..2500


EXAMPLE

a(6) = 10, since the sum of aliquot divisors 1 + 2 + 5 = 8 = 2^3.


MAPLE

for n do s:=numtheory[sigma](n)n; if root(s, 3)=trunc(root(s, 3)) then print(n); fi; od:


MATHEMATICA

Select[Range[250], IntegerQ[Power[DivisorSigma[1, #]#, (3)^1]]&] (* Harvey P. Dale, Nov 25 2011 *)


CROSSREFS

Cf. A020477, A073040.
Sequence in context: A235050 A117286 A169802 * A191211 A254860 A144726
Adjacent sequences: A194945 A194946 A194947 * A194949 A194950 A194951


KEYWORD

nonn


AUTHOR

Martin Renner, Oct 13 2011


STATUS

approved



