login
A355450
a(n) = 1 if n is odd and phi(x) = n^2 + 1 has no solutions, otherwise 0.
2
0, 0, 0, 0, 1, 0, 1, 0, 0, 0, 1, 0, 1, 0, 0, 0, 1, 0, 1, 0, 0, 0, 1, 0, 1, 0, 1, 0, 1, 0, 1, 0, 0, 0, 1, 0, 1, 0, 0, 0, 1, 0, 1, 0, 0, 0, 1, 0, 1, 0, 1, 0, 1, 0, 1, 0, 0, 0, 1, 0, 1, 0, 1, 0, 1, 0, 1, 0, 1, 0, 1, 0, 1, 0, 1, 0, 1, 0, 1, 0, 0, 0, 1, 0, 1, 0, 1, 0, 1, 0, 1, 0, 1, 0, 1, 0, 1, 0, 0, 0, 1, 0, 1, 0, 0, 0, 1, 0, 1, 0, 0, 0, 1, 0, 1, 0, 0, 0, 1, 0, 1, 0, 0, 0, 1
OFFSET
1
FORMULA
a(n) = A355451(1 + n^2).
PROG
(PARI)
A355451(n) = (!(n%2) && !istotient(n));
A355450(n) = A355451(1+(n^2));
CROSSREFS
Characteristic function of A106571.
Cf. A355451.
Sequence in context: A353464 A144193 A171387 * A333189 A011662 A011665
KEYWORD
nonn
AUTHOR
Antti Karttunen, Jul 12 2022
STATUS
approved