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 A164266 The count of primes between the n-th and (n+1)-st perfect number. 0
 6, 85, 928, 2062427, 391549471, 5192879231 (list; graph; refs; listen; history; text; internal format)
 OFFSET 1,1 LINKS Table of n, a(n) for n=1..6. FORMULA a(n) = A000720(A000396(n+1)) - A000720(A000396(n)). EXAMPLE a(1)=6 counts the 6 primes 7, 11, 13, 17, 19 and 23 between 6 and 28. a(2)=85 counts the 85 primes 29, 31, ..., 487, 491 between 28 and 496. MATHEMATICA PrimePi[Last[#]]-PrimePi[First[#]]&/@(Partition[(# (#+1))/2&/@ Select[ 2^Range[30]-1, PrimeQ], 2, 1]) (* Harvey P. Dale, Dec 27 2011 *) CROSSREFS Cf. A000040, A000396. Sequence in context: A284522 A167252 A290011 * A136597 A064329 A187740 Adjacent sequences: A164263 A164264 A164265 * A164267 A164268 A164269 KEYWORD nonn,hard AUTHOR Juri-Stepan Gerasimov, Aug 11 2009 EXTENSIONS Edited by R. J. Mathar, Aug 26 2009 More terms from Harvey P. Dale, Dec 27 2011 STATUS approved

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Last modified May 23 01:37 EDT 2024. Contains 372758 sequences. (Running on oeis4.)