A100923 a(n) = 1 iff 6*n+1 and 6*n-1 are both prime numbers (0 otherwise).

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

Offset

1,1

Comments

Characteristic function of A002822. - Georg Fischer, Aug 04 2021

Links

Table of n, a(n) for n=1..105.

Example

a(3) = 1 because 6*3-1=17 and 6*3+1=19 are both prime.
a(4) = 0 because 6*4-1=23 is prime and 6*4+1=25 is not prime.
a(20) = 0 because 6*20-1=119 and 6*20+1=121 are both not prime.

Mathematica

Table[If[And[PrimeQ[6*k - 1], PrimeQ[6*k + 1]], 1, 0], {k, 1, 110}]

Crossrefs

Cf. A000040, A002822, A100924, A100925.

Sequence in context: A369253 A167752 A240025 * A050073 A266843 A373486

Adjacent sequences: A100920 A100921 A100922 * A100924 A100925 A100926

Keyword

nonn

Author

Joseph Biberstine (jrbibers(AT)indiana.edu), Nov 22 2004

Status

approved