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A289495
Number of primes in the interval [4n, 5n].
8
1, 0, 1, 2, 1, 1, 2, 1, 3, 3, 2, 2, 3, 3, 4, 4, 4, 4, 3, 3, 4, 6, 6, 6, 5, 4, 4, 5, 4, 5, 6, 6, 6, 7, 6, 7, 8, 6, 8, 9, 8, 7, 8, 7, 7, 8, 9, 9, 9, 7, 8, 9, 9, 10, 11, 11, 12, 11, 11, 10, 9, 10, 11, 12, 11, 10, 11, 10, 10, 11, 10, 11, 11, 11, 12
OFFSET
1,4
LINKS
PROG
(PARI) a(n) = primepi(5*n) - primepi(4*n); \\ Michel Marcus, Jul 08 2017
KEYWORD
nonn,easy
AUTHOR
FUNG Cheok Yin, Jul 07 2017
STATUS
approved