A054022 Chowla function of n is divisible by the number of divisors of n.

1, 2, 3, 5, 7, 9, 11, 13, 15, 17, 19, 23, 27, 29, 31, 32, 35, 36, 37, 39, 41, 43, 47, 50, 51, 53, 55, 59, 61, 67, 71, 73, 75, 79, 83, 87, 89, 91, 95, 97, 98, 101, 103, 107, 109, 111, 113, 115, 119, 123, 127, 131, 135, 137, 139, 143, 149, 151, 155, 157, 159, 162, 163

Offset: 1

Author

Asher Auel, Jan 19 2000

Keywords

• nonn

Comments

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

Links

• Harvey P. Dale, Table of n, a(n) for n = 1..1000

Crossrefs

Complement is A054023 Cf. A000005, A048050, A054014.

Programs

Maple

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

Mathematica

Select[Range[200],Divisible[DivisorSigma[1,#]-1-#,DivisorSigma[0,#]]&] (* Harvey P. Dale, Mar 11 2012 *)