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A309333
The number of primes between two consecutive lucky primes, bounds excluded.
2
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
OFFSET
1,3
LINKS
EXAMPLE
a(1): Between the first two lucky primes (3, 7) there is one prime (5).
a(3): Between 13 and 31 there 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
KEYWORD
nonn
AUTHOR
Hauke Löffler, Jul 24 2019
STATUS
approved