

A079629


Number of twin prime pairs between p^2 and q^2 where (p,q) is the nth twin prime pair.


4



2, 2, 2, 2, 2, 3, 5, 3, 7, 6, 6, 10, 13, 7, 8, 9, 9, 7, 12, 18, 14, 24, 19, 10, 21, 21, 20, 20, 19, 22, 19, 24, 24, 27, 25, 30, 27, 23, 34, 29, 21, 35, 38, 30, 32, 30, 33, 36, 33, 30
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OFFSET

1,1


COMMENTS

Conjecturally a(n) is always positive. It seems that a(n) might tend to infinity.
a(n) = A071538(A006512(n)^2)  A071538(A001359(n)^2).  Reinhard Zumkeller, Feb 16 2008


LINKS

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


EXAMPLE

a(3)=2 because the third twin prime pair is (11,13) and there are 2 twin prime pairs between 121 and 169, namely (137,139) and (149,151).


MATHEMATICA

ntpp[{a_, b_}]:=Count[Differences[Select[Range[a^2+1, b^2], PrimeQ]], 2]; ntpp/@ Select[Partition[Prime[Range[300]], 2, 1], #[[2]]#[[1]]==2&] (* Harvey P. Dale, Oct 04 2019 *)


CROSSREFS

Cf. A057767.
Cf. A137859, A137860.
Sequence in context: A029105 A079954 A114968 * A029116 A064770 A322073
Adjacent sequences: A079626 A079627 A079628 * A079630 A079631 A079632


KEYWORD

easy,nonn


AUTHOR

Paul Boddington, Jan 30 2003


STATUS

approved



