

A309333


The number of primes between two consecutive lucky primes, bounds excluded.


1



1, 1, 4, 0, 1, 4, 1, 0, 8, 4, 1, 5, 2, 0, 4, 7, 1, 3, 2, 2, 6, 1, 1, 5, 2, 6, 5, 3, 1, 1, 0, 1, 4, 6, 1, 4, 1, 4, 9, 5, 7, 0, 0, 2, 2, 5, 1, 3, 0, 8, 4, 1, 5, 2, 18, 0, 9, 3, 1, 1, 9, 2, 4, 5, 3, 2, 6, 5, 4, 9, 3, 4, 11, 1, 1, 3, 4, 20, 0, 8, 2, 4, 3, 3, 15, 6
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OFFSET

1,3


LINKS

Table of n, a(n) for n=1..86.


EXAMPLE

a(1): Between the first two lucky primes (3, 7) is one prime (5).
a(3): Between 13 and 31 are 4 primes (17, 19, 23, 29).


PROG

(SageMath)
def count_primes_between(a, b):
return len(prime_range(a+1, b))
[count_primes_between(A031157[i], A031157[i+1]) for i in range (len(A031157[0:20])1)]


CROSSREFS

Cf. A031157, A309334, A176559.
Sequence in context: A172545 A124321 A232195 * A298924 A217476 A298622
Adjacent sequences: A309330 A309331 A309332 * A309334 A309335 A309336


KEYWORD

nonn


AUTHOR

Hauke Löffler, Jul 24 2019


STATUS

approved



