A060678 Numbers n such that sigma (x) = n has exactly 11 solutions.

576, 1296, 2976, 3168, 3648, 3720, 4788, 4896, 5544, 6300, 9000, 9840, 10656, 11808, 12528, 13020, 13320, 14760, 15456, 16740, 17920, 18288, 18576, 19344, 19840, 20400, 21280, 22800, 23296, 24300, 26712, 26928, 27552, 27936, 28392

Offset

1,1

Links

Table of n, a(n) for n=1..35.

Example

576 = sigma(210) = sigma(282) = sigma(310) = sigma(322) = sigma(345) = sigma(357) = sigma(382) = sigma(385) = sigma(497) = sigma(517) = sigma(527).

Mathematica

a = Table[ 0, {30000} ]; Do[ s = DivisorSigma[ 1, n ]; If[ s < 30001, a[ [ s ] ]++ ], {n, 1, 30000} ]; Select[ Range[ 30000 ], a[ [ # ] ] == 11 & ]

Crossrefs

Cf. A007370, A007371, A007372.

Sequence in context: A258919 A064253 A069266 * A254848 A235181 A268773

Adjacent sequences: A060675 A060676 A060677 * A060679 A060680 A060681

Keyword

nonn

Author

Robert G. Wilson v, Apr 18 2001

Status

approved