A075743 - OEIS

A075743

For all numbers of the form 6*k +- 1 starting with 5, '1' indicates prime and '0' indicates composite.

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

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OFFSET

1,1

COMMENTS

The sequence may described as: for all numbers k(n) [k(n) = 6*ceiling(n/2) + (-1)^n] congruent to -1 or +1 (mod 6) starting with k(n) = {5,7,11,13,...}, a(k(n)) is 1 if k(n) is prime and 0 if k(n) is composite. - Daniel Forgues, Mar 01 2009

LINKS

Daniel Forgues, Table of n, a(n) for n = 1..33332

FORMULA

a(n) = A010051(A007310(n+1)). - Reinhard Zumkeller, Oct 02 2008

a(n) = A090405(3*n). - Ridouane Oudra, Feb 25 2026

MATHEMATICA

Boole[PrimeQ/@Flatten[Table[6n+{-1, 1}, {n, 60}]]] (* Harvey P. Dale, Jun 04 2017 *)

CROSSREFS

Cf. A000040, A000720, A007310, A010051, A090405.

Absolute value of A156706.

Sequence in context: A167686 A190207 A156706 * A136705 A141646 A129573

Adjacent sequences: A075740 A075741 A075742 * A075744 A075745 A075746