A309333 The number of primes between two consecutive lucky primes, bounds excluded.

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

Amiram Eldar, Table of n, a(n) for n = 1..10000

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

Cf. A000959, 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