

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
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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



PROG

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


CROSSREFS



KEYWORD

nonn


AUTHOR



EXTENSIONS



STATUS

approved



