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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 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,4

LINKS

FUNG Cheok Yin, Table of n, a(n) for n = 1..10000

PROG

(PARI) a(n) = primepi(5*n) - primepi(4*n); \\ Michel Marcus, Jul 08 2017

CROSSREFS

Cf. A035250, A289493, A289494, A289496, A289497, A289498, A289499, A289500.

Sequence in context: A236508 A239000 A105248 * A076302 A104524 A233322

Adjacent sequences:  A289492 A289493 A289494 * A289496 A289497 A289498

KEYWORD

nonn,easy

AUTHOR

FUNG Cheok Yin, Jul 07 2017

STATUS

approved

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Last modified February 20 22:47 EST 2020. Contains 332086 sequences. (Running on oeis4.)