A071707 - OEIS

A071707

Numbers k that divide tau(k)*sigma(k).

1, 2, 6, 12, 18, 24, 28, 40, 84, 120, 224, 234, 240, 252, 360, 468, 496, 672, 864, 936, 1638, 1920, 2016, 2480, 3276, 4320, 4680, 6048, 6528, 6552, 7440, 8128, 9360, 10880, 22320, 22932, 26208, 30240, 32640, 32760, 47616, 56896, 58752, 65520, 74880, 79360, 84480

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OFFSET

1,2

LINKS

Donovan Johnson, Table of n, a(n) for n = 1..300

EXAMPLE

The divisors of 18 are {1,2,3,6,9,18}, so tau(18)=6 and sigma(18)=1+2+3+6+9+18=39, 18 is a term as 18*13=6*39=tau(18)*sigma(18).

CROSSREFS

Cf. A007691, A064840(n)=A000005(n)*A000203(n).

Sequence in context: A043343 A066080 A319270 * A069087 A367504 A304450

Adjacent sequences: A071704 A071705 A071706 * A071708 A071709 A071710

KEYWORD

nonn

AUTHOR

Reinhard Zumkeller, Jun 03 2002

STATUS

approved