A256737 Number of composites lying between successive pairs of primes, beginning with pair (2,3). Bisection of A046933.

0, 1, 1, 1, 5, 5, 1, 5, 1, 3, 5, 5, 3, 3, 3, 3, 1, 1, 5, 5, 1, 1, 1, 11, 1, 5, 9, 5, 1, 3, 9, 3, 3, 5, 1, 5, 5, 3, 7, 7, 1, 1, 3, 7, 1, 11, 3, 3, 11, 17, 9, 5, 5, 5, 1, 5, 1, 9, 3, 5, 11, 5, 9, 9, 5, 3, 5, 7, 13, 11, 9, 3, 9, 3, 3, 3, 3, 3, 9, 3, 5, 3, 5, 5, 3, 1, 1, 9, 9, 5, 3, 3, 5, 5, 21

Offset: 1

Author

Peter Woodward, Apr 09 2015

Keywords

• nonn

Examples

			For the third term in the sequence, use prime pair (11,13). Only composite that lies between is "12", thus the third value in the sequence is "1".
		

Crossrefs

Complement of A256736 with respect to A046933.

Programs

Mathematica

Flatten[Differences/@Partition[Prime[Range[200]],2]]-1 (* Harvey P. Dale, Dec 17 2023 *)

PARI

a(n)=my(q=prime(2*n)); q-precprime(q-1)-1 \\ Charles R Greathouse IV, Apr 21 2015