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A088228 Number of composite numbers between the smallest primes that surround n# and n#+n. n# = n primorial = product of primes <= n. 1
1, 4, 6, 22, 22, 17, 47, 45, 79, 101, 138, 119, 71, 135, 173, 131, 167, 197, 189, 229, 175, 233, 285, 101, 353, 363, 335, 277, 485, 441, 385, 407, 1031, 519, 307, 363, 611, 477, 431, 381, 421, 605, 525, 1343, 605, 1229 (list; graph; refs; listen; history; text; internal format)
OFFSET

2,2

LINKS

Harvey P. Dale, Table of n, a(n) for n = 2..200

MATHEMATICA

Count[#, _?CompositeQ]&/@(Module[{pr=Prime[Range[50]]}, Range[ NextPrime[ Last[#], -1]+1, NextPrime[Total[#]]-1]&/@Thread[{pr, Rest[ FoldList[ Times, 1, pr]]}]]) (* Harvey P. Dale, Aug 03 2014 *)

PROG

(PARI) primorialgaps(m) = { forprime(n=2, m, c=0; np=primorial(n); for(x=precprime(np), nextprime(np+n), if(!isprime(x), c++)); print1(c", ") ) } primorial(k) = { p=1; forprime(z=1, k, p*=z); return(p) }

CROSSREFS

Sequence in context: A227249 A002270 A286358 * A272309 A108636 A101143

Adjacent sequences:  A088225 A088226 A088227 * A088229 A088230 A088231

KEYWORD

nonn

AUTHOR

Cino Hilliard, Nov 04 2003

STATUS

approved

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Last modified June 27 08:21 EDT 2017. Contains 288777 sequences.