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A101808 Number of primes between two consecutive even numbers. 0
1, 2, 1, 1, 0, 1, 1, 0, 1, 1, 0, 1, 0, 0, 1, 1, 0, 0, 1, 0, 1, 1, 0, 1, 0, 0, 1, 0, 0, 1, 1, 0, 0, 1, 0, 1, 1, 0, 0, 1, 0, 1, 0, 0, 1, 0, 0, 0, 1, 0, 1, 1, 0, 1, 1, 0, 1, 0, 0, 0, 0, 0, 0, 1, 0, 1, 0, 0, 1, 1, 0, 0, 0, 0, 1, 1, 0, 0, 1, 0, 0, 1, 0, 1, 0, 0, 1, 0, 0, 1, 1, 0, 0, 0, 0, 1, 1, 0, 1, 1, 0, 0, 0, 0, 0 (list; graph; refs; listen; history; text; internal format)
OFFSET

0,2

LINKS

Table of n, a(n) for n=0..104.

FORMULA

a(n)=A101264(n), n>1. [From R. J. Mathar, Dec 13 2008]

EXAMPLE

a(1)=2 because between 2 and 4 there are two primes: 2,3;

a(2)=1 because between 4 and 6 there is one prime: 5;

a(4)=0 because between 8 and 10 there are no primes.

PROG

(PARI) a(n) = if (n==0, 1, if (n==1, 2, isprime(2*n+1))) \\ Michel Marcus, Jun 03 2013

CROSSREFS

Sequence in context: A133699 A157361 A224444 * A145865 A076452 A076453

Adjacent sequences:  A101805 A101806 A101807 * A101809 A101810 A101811

KEYWORD

easy,nonn

AUTHOR

Giovanni Teofilatto, Jan 27 2005

STATUS

approved

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Last modified March 28 05:38 EDT 2020. Contains 333073 sequences. (Running on oeis4.)