A137859 Number of primes between the n-th squared twin prime pair.

5, 6, 9, 11, 16, 20, 32, 30, 42, 42, 49, 58, 76, 77, 75, 82, 90, 91, 99, 107, 125, 151, 151, 145, 165, 189, 168, 189, 194, 211, 241, 244, 246, 259, 262, 290, 304, 300, 311, 314

Offset: 1

Author

Reinhard Zumkeller, Feb 16 2008

Keywords

• nonn

Comments

a(n) = SUM(A010051(k): A006512(n)^2 <= k <= A001359(n)^2) =

A000720(A006512(n)^2)-A000720(A001359(n)^2).

Examples

			a(4) = #{293,307,311,313,317,331,337,347,349,353,359} = 11.
		

Links

• Harvey P. Dale, Table of n, a(n) for n = 1..1000

Crossrefs

Cf. A079629, A137860.

Programs

Mathematica

PrimePi[#[[2]]^2]-PrimePi[#[[1]]^2]&/@Select[Partition[ Prime[ Range[ 200]],2,1],#[[2]]-#[[1]]==2&] (* Harvey P. Dale, Nov 10 2017 *)