A378901 a(n) = 0 if s(n) is nonprime, a(n) = 1 if s(n) is prime, where s = A005117.

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

Offset

1

Comments

Characteristic function of prime squarefree numbers.

First differences of pi(s(n)) = A000720(A005117(n)).

Links

Michael De Vlieger, Table of n, a(n) for n = 1..10000

Formula

a(k) = 1 for k in A071403.

Mathematica

Map[Boole[PrimeQ[#]] &, Select[Range[120], SquareFreeQ] ]

Crossrefs

Cf. A000040, A000720, A005117, A071403.

Sequence in context: A190201 A189702 A168395 * A278718 A130854 A165191

Adjacent sequences: A378898 A378899 A378900 * A378902 A378903 A378909

Keyword

nonn,easy,new

Author

Michael De Vlieger, Dec 12 2024

Status

approved