A364251 a(n) = 1 if n is of the form q*(2^k), where q is one of the Mersenne primes (A000668) and k >= 0, otherwise a(n) = 0.

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

Offset

1

Links

Antti Karttunen, Table of n, a(n) for n = 1..65537

Index entries for characteristic functions

Formula

a(n) = [A331410(n) == 1], where [ ] is the Iverson bracket.

a(n) = [A364260(n) == 1].

a(n) <= A336923(n) <= A364252(n).

Prog

(PARI)
isA000668(n) = (isprime(n)&&!bitand(n, 1+n));
A364251(n) = isA000668(n>>valuation(n, 2));

Crossrefs

Characteristic function of A335431.

Cf. A000668, A331410, A364260.

Cf. also A336923, A364252.

Sequence in context: A028999 A091244 A189632 * A365421 A131378 A354029

Adjacent sequences: A364248 A364249 A364250 * A364252 A364253 A364254

Keyword

nonn

Author

Antti Karttunen, Jul 16 2023

Status

approved