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A258972
Number of other odd numbers between the twin primes, with a(1) = 1.
0
1, 1, 1, 4, 4, 7, 4, 13, 1, 13, 4, 13, 4, 1, 13, 4, 13, 4, 13, 16, 34, 4, 13, 28, 22, 13, 7, 10, 7, 73, 4, 1, 13, 10, 67, 4, 7, 4, 13, 28, 37, 22, 4, 4, 7, 52, 10, 13, 1, 58, 4, 22, 13, 10, 31, 40, 1, 25, 7, 22, 13, 25, 1, 10, 7, 4, 46, 13, 19, 13, 19, 82, 19, 31, 13, 10, 7, 28, 4, 82, 13, 58, 22, 40, 1, 19, 13, 13, 4, 7, 34, 1
OFFSET
1,4
COMMENTS
Bisection of A256262.
FORMULA
a(n) = abs((A001359(n+1) - A001359(n))/2 - 2).
a(n) = abs((A006512(n+1) - A006512(n))/2 - 2).
EXAMPLE
--------------------------------------------
. Other Twin
. odd numbers primes
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1 1 3, 5, 7 1
2 9 11, 13 1
3 15 17, 19 1
4 21, 23, 25, 27 29, 31 4
5 33, 35, 37, 39 41, 43 4
...
For n = 5, between the successive pairs of twin primes [29, 31] and [41, 43] there are four odd numbers that are not twin primes: 33, 35, 37, 39, so a(5) = 4.
CROSSREFS
KEYWORD
nonn
AUTHOR
Omar E. Pol, Jun 15 2015
STATUS
approved