A256736 Number of composites lying between successive pairs of primes, beginning with pair (3,5). Bisection of A046933.

1, 3, 3, 3, 1, 3, 3, 5, 5, 1, 3, 7, 1, 1, 13, 5, 9, 5, 3, 5, 9, 3, 11, 3, 3, 1, 5, 5, 5, 1, 13, 1, 13, 9, 3, 7, 5, 5, 3, 9, 9, 5, 5, 3, 3, 7, 7, 5, 1, 5, 5, 1, 9, 5, 5, 3, 11, 1, 5, 1, 3, 7, 7, 7, 5, 7, 3, 3, 9, 1, 1, 1, 13, 1, 13, 1, 19, 7, 7, 5, 13, 5, 7, 11

Offset: 1

Author

Peter Woodward, Apr 09 2015

Keywords

• nonn

Examples

			[3,5] contains 4, so a(1)=4.
[7,11] contains 8,9,10, so a(2)=3.
For the third term in the sequence, use prime pair [13,17]. There are three composites between 13 and 17, thus the third term = 3.
		

Links

• Jinyuan Wang, Table of n, a(n) for n = 1..1000

Crossrefs

Complement of A256737 in regards to forming A046933.

Programs

Mathematica

Table[Prime[n + 1] - Prime[n] - 1, {n, 2, 100, 2}] (* Hartmut F. W. Hoft, Apr 24 2015 *)

PARI

a(n) = prime(2*n+1)-prime(2*n)-1; \\ Jinyuan Wang, Jul 09 2020

Extensions

Corrected and extended by Hartmut F. W. Hoft, Apr 24 2015

More terms from Robert G. Wilson v, May 03 2015