login
A156706
For all numbers k(n) congruent to +1 or -1 (mod 6) starting with k(n) = {5,7,11,13,...}, a(k(n)) is the congruence (mod 6) if k(n) is prime and 0 if k(n) is composite.
5
-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
OFFSET
1,1
COMMENTS
Expression for k(n): k(n) = 6*ceiling(n/2) + (-1)^n, so the parity of n gives us the congruence (mod 6) of k(n). - Daniel Forgues, Mar 01 2009
LINKS
CROSSREFS
Cf. A075743.
The absolute values of this sequence give A075743. The partial sums of this sequence give A156709.
Sequence in context: A341952 A167686 A190207 * A075743 A136705 A141646
KEYWORD
sign
AUTHOR
Daniel Forgues, Feb 13 2009, Feb 14 2009
STATUS
approved