

A054021


Numbers n such that Chowla's function of n is divisible by the number of proper divisors of n.


2



2, 3, 4, 5, 7, 8, 11, 12, 13, 14, 17, 18, 19, 23, 24, 26, 27, 29, 31, 32, 35, 37, 38, 40, 41, 43, 47, 52, 53, 56, 59, 61, 62, 63, 65, 66, 67, 71, 73, 74, 77, 79, 83, 86, 88, 89, 90, 92, 95, 97, 101, 103, 104, 107, 109, 110, 112, 113, 119, 122, 125, 127, 128, 131, 134, 136
(list;
graph;
refs;
listen;
history;
text;
internal format)



OFFSET

1,1


COMMENTS

Chowla's function (A048050) = sum of divisors of n except 1 and n.


LINKS

Amiram Eldar, Table of n, a(n) for n = 1..10000


MAPLE

with(numtheory):
[seq(`if`((sigma(i)i1) mod (tau(i)1)=0, i, print( )), i=2..1000)];


MATHEMATICA

Select[Range[2, 150], Divisible[DivisorSigma[1, #]1#, DivisorSigma[ 0, #]1]&] (* Harvey P. Dale, Aug 13 2018 *)


CROSSREFS

Complement is A054020.
Cf. A032741, A048050, A054015.
Sequence in context: A214036 A100289 A255130 * A066191 A166159 A169693
Adjacent sequences: A054018 A054019 A054020 * A054022 A054023 A054024


KEYWORD

nonn


AUTHOR

Asher Auel (asher.auel(AT)reed.edu), Jan 19 2000


STATUS

approved



