OFFSET
1,1
COMMENTS
Characteristic function of A002822. - Georg Fischer, Aug 04 2021
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
KEYWORD
nonn
AUTHOR
Joseph Biberstine (jrbibers(AT)indiana.edu), Nov 22 2004
STATUS
approved