A355451 a(n) = 1 if n is even and phi(x) = n has no solutions, otherwise 0.

0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 1, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 1, 0, 0, 0, 0, 0, 0, 0, 1, 0, 0, 0, 1, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 1, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 1, 0, 0, 0, 0, 0, 1, 0, 0, 0, 0, 0, 1, 0, 1, 0, 0, 0, 0, 0, 0, 0, 0, 0, 1, 0, 0, 0, 1, 0, 0, 0, 1, 0, 0, 0, 1, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 1, 0, 0, 0, 1, 0, 0, 0, 1, 0, 1, 0

Offset

1

Links

Antti Karttunen, Table of n, a(n) for n = 1..100000

Index entries for characteristic functions

Formula

a(n) = A059841(n) * (1-A264739(n));

For n > 2, a(n) >= A355452(n).

Prog

(PARI) A355451(n) = (!(n%2) && !istotient(n));

Crossrefs

Characteristic function of A005277.

Cf. A000010, A059841, A014197, A264739, A355450, A355452.

Sequence in context: A216038 A011728 A297043 * A133010 A234323 A162782

Adjacent sequences: A355448 A355449 A355450 * A355452 A355453 A355454

Keyword

nonn

Author

Antti Karttunen, Jul 12 2022

Status

approved