A231167 a(1) = a(2) = 0, for n>=3: (sum of non-divisors of n) modulo (number of non-divisors of n).

0, 0, 0, 0, 0, 1, 0, 1, 2, 1, 0, 2, 0, 1, 8, 6, 0, 0, 0, 0, 12, 1, 0, 0, 8, 1, 16, 20, 0, 19, 0, 23, 20, 1, 24, 8, 0, 1, 24, 26, 0, 25, 0, 32, 21, 1, 0, 26, 18, 38, 32, 38, 0, 31, 40, 36, 36, 1, 0, 30, 0, 1, 31, 15, 48, 37, 0, 50, 44, 47, 0, 33, 0, 1, 35, 56

Offset

1,9

Comments

a(n) = 0 for n = 1, 2 and numbers from A140826.

a(n) = 1 for numbers of form 2*p (p=prime) from A100484 and other numbers, e.g. 8 and 13456 are only numbers n < 10^5 which are not of form 2*p with a(n) = 1.

Links

Jaroslav Krizek, Table of n, a(n) for n = 1..10000

Formula

a(n) = A024816(n) mod A049820(n).

Example

For n=6, a(6) = A024816(6) mod A049820(6) = 9 mod 2 = 1.

Mathematica

ndn[n_]:=Module[{nd=Complement[Range[n], Divisors[n]]}, Mod[Total[ nd], Length[ nd]]]; Join[{0, 0}, Array[ndn, 80, 3]] (* Harvey P. Dale, Apr 11 2022 *)

Crossrefs

Cf. A054025 (sigma(n) mod tau(n)), A024816, A049820, A024816, A049820, A065091, A230605, A161344.

Sequence in context: A348128 A328777 A244553 * A194313 A127476 A140397

Adjacent sequences: A231164 A231165 A231166 * A231168 A231169 A231170

Keyword

nonn

Author

Jaroslav Krizek, Nov 07 2013

Status

approved