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

1,5

Links

Table of n, a(n) for n=1..95.

Example

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".

Mathematica

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

Prog

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

Crossrefs

Complement of A256736 with respect to A046933.

Sequence in context: A282969 A046095 A322545 * A055183 A198740 A082956

Adjacent sequences: A256734 A256735 A256736 * A256738 A256739 A256740

Keyword

nonn

Author

Peter Woodward, Apr 09 2015

Status

approved