A075424 a(n) = A075423(A075423(n)).

0, 1, 0, 1, 4, 5, 0, 1, 2, 9, 4, 5, 12, 13, 0, 1, 4, 5, 2, 9, 20, 21, 4, 1, 4, 1, 12, 13, 28, 29, 0, 1, 32, 33, 4, 5, 36, 37, 2, 9, 40, 41, 20, 13, 14, 45, 4, 5, 2, 9, 4, 25, 4, 5, 12, 13, 56, 57, 28, 29, 60, 9, 0, 1, 64, 65, 32, 33, 68, 69, 4, 5, 72, 13, 36, 37, 76, 77, 2, 1, 2, 81, 40, 41

Offset: 2

Author

Reinhard Zumkeller, Sep 15 2002

Keywords

• nonn
• look

Comments

From Robert Israel, Apr 11 2019: (Start)

a(n) == n (mod 2).

a(n) = 0 iff n is in A000079.

a(n) = n-2 iff n-1 is in A007674. (End)

Links

• Robert Israel, Table of n, a(n) for n = 2..10000

Crossrefs

Cf. A000079, A007674, A075423, A075425.

Programs

Maple

A075423:= n -> convert(numtheory:-factorset(n),`*`)-1:
map(A075423@@2, [$2..100]); # Robert Israel, Apr 11 2019