A242902 a(n) = 1 if either of A014574(n) + A014574(n+2) +- 1 is prime or 0 otherwise.

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

Offset

1

Comments

From the first 10000 evaluations (each evaluating the primality of 2 values, though at least 2200 are obvious as multiples of 5), one encounters ~5200 primes. The longest "gap" without prime encounter is 13 evaluations. By design, the procedure encounters primes loosely on the order of twice as large as those used in each evaluation.

Links

Charles R Greathouse IV, Table of n, a(n) for n = 1..10000

Example

A014574(2)=6 and A014574(4)=18. (18+6) +-1 yields 23, 25. 23 is prime, so a(2)=1.
A014574(12)=150 and A014574(14)=192, which yields 341, 343. Neither is prime, so a(12)=0.

Prog

(PARI) v=[0, 4, 6]; p=11; forprime(q=13, , if(q-p==2, v=[v[2], v[3], p+1]; print1(isprime(v[1]+v[3]+1)||isprime(v[1]+v[3]-1), ", ")); p=q) \\ Charles R Greathouse IV, May 25 2014

Crossrefs

Cf. A014574.

Sequence in context: A123927 A089829 A294935 * A196368 A178788 A131217

Adjacent sequences: A242899 A242900 A242901 * A242903 A242904 A242905

Keyword

nonn

Author

Bill McEachen, May 25 2014

Status

approved