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A256736
Number of composites lying between successive pairs of primes, beginning with pair (3,5). Bisection of A046933.
2
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
1,2
LINKS
EXAMPLE
[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.
MATHEMATICA
Table[Prime[n + 1] - Prime[n] - 1, {n, 2, 100, 2}] (* Hartmut F. W. Hoft, Apr 24 2015 *)
PROG
(PARI) a(n) = prime(2*n+1)-prime(2*n)-1; \\ Jinyuan Wang, Jul 09 2020
CROSSREFS
Complement of A256737 in regards to forming A046933.
Sequence in context: A167817 A153401 A181520 * A372700 A123073 A059289
KEYWORD
nonn
AUTHOR
Peter Woodward, Apr 09 2015
EXTENSIONS
Corrected and extended by Hartmut F. W. Hoft, Apr 24 2015
More terms from Robert G. Wilson v, May 03 2015
STATUS
approved