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A101597 Number of consecutive composite numbers between balanced primes and their lower or upper prime neighbor. 1
1, 5, 5, 5, 11, 5, 5, 5, 5, 5, 5, 5, 5, 5, 5, 5, 5, 5, 5, 5, 11, 5, 5, 5, 5, 5, 5, 5, 5, 5, 5, 5, 5, 5, 11, 5, 5, 5, 11, 5, 5, 5, 5, 5, 5, 5, 5, 5, 5, 5, 5, 5, 5, 5, 5, 5, 5, 5, 11, 5, 5, 5, 5, 5, 11, 5, 5, 5, 5, 11, 11, 5, 11, 5, 5, 5, 5, 5, 5, 5, 5, 11, 5, 5, 5, 5, 5, 5, 5, 5, 11, 5, 5, 5, 5, 5, 5, 5, 5, 5 (list; graph; refs; listen; history; text; internal format)
OFFSET

2,2

COMMENTS

These numbers are not always prime with 35 occurring for prime(n) n<1000000.

LINKS

Table of n, a(n) for n=2..101.

EXAMPLE

53 has the 5 consecutive composites 48,49,50,51,52 below it and the 5 consecutive composites 54,55,56,57,58 above it so 5 is in the second position in the table.

PROG

(PARI) betwixtpr(n) = { local(c1, c2, x, y); for(x=2, n, c1=c2=0; for(y=prime(x-1)+1, prime(x)-1, if(!isprime(y), c1++); ); for(y=prime(x)+1, prime(x+1)-1, if(!isprime(y), c2++); ); if(c1==c2, print1(c1", ")) ) }

CROSSREFS

Sequence in context: A135089 A127310 A214925 * A119991 A262947 A265821

Adjacent sequences:  A101594 A101595 A101596 * A101598 A101599 A101600

KEYWORD

nonn

AUTHOR

Cino Hilliard, Jan 26 2005

STATUS

approved

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Last modified July 25 04:48 EDT 2017. Contains 289779 sequences.