A164266 The count of primes between the n-th and (n+1)-st perfect number.

6, 85, 928, 2062427, 391549471, 5192879231

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