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A113939 Numbers n such that sigma(n) and phi(n) are both perfect cubes. 0
1, 300118, 2250885, 5294800, 76336260, 141483384, 242375035, 453280968, 456345036, 461356896, 478240392, 537375930, 1139523375, 1180718238, 1227111595, 1599634410, 5043835125, 5229921340, 5610392513, 6087775939 (list; graph; refs; listen; history; internal format)
OFFSET

1,2

COMMENTS

phi(n)=A000010(n) is the Euler totient function, while sigma(n)=A000203(n) is the sum of divisors of n

EXAMPLE

sigma(2250885)=168^3 and phi(2250885)=96^3.

CROSSREFS

Cf. A000010, A000203.

Sequence in context: A119740 A022246 A050257 * A023686 A156998 A156999

Adjacent sequences:  A113936 A113937 A113938 * A113940 A113941 A113942

KEYWORD

nonn

AUTHOR

Giovanni Resta (g.resta(AT)iit.cnr.it), Jan 31 2006

EXTENSIONS

a(7)-a(20) from Donovan Johnson (donovan.johnson(AT)yahoo.com), Feb 06 2010

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Last modified February 16 16:34 EST 2012. Contains 205938 sequences.