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A204099
Number of integers between successive twin prime pairs.
5
0, 3, 3, 9, 9, 15, 9, 27, 3, 27, 9, 27, 9, 3, 27, 9, 27, 9, 27, 33, 69, 9, 27, 57, 45, 27, 15, 21, 15, 147, 9, 3, 27, 21, 135, 9, 15, 9, 27, 57, 75, 45, 9, 9, 15, 105, 21, 27, 3, 117, 9, 45, 27, 21, 63, 81, 3, 51, 15, 45, 27, 51, 3, 21, 15, 9, 93, 27, 39
OFFSET
1,2
COMMENTS
a(n) is divisible by 3.
LINKS
FORMULA
a(n) = A167132(n) - 1.
a(n) = A063091(n+1) - A063091(n) - 3.
EXAMPLE
a(1) = 0 because (3,5) is adjacent to (5,7); a(2) = 3 because the numbers 8, 9 and 10 are between (5,7) and (11,13), ...
MAPLE
T:=array(1..100, 1..2):k:=0:for n from 1 to 1000 do:p1:=ithprime(n):p2:=ithprime(n+1):if p2-p1 = 2 then k:=k+1:T[k, 1]:=p1:T[k, 2]:=p2:else fi:od: for p from 2 to k do:x:= T[p+1, 1]- T[p, 2]: printf(`%d, `, x-1):od:
MATHEMATICA
Module[{tr=Transpose[Select[Partition[Prime[Range[450]], 2, 1], #[[2]]- #[[1]] == 2&]], fir, las}, fir=Rest[tr[[1]]]; las=Most[tr[[2]]]; Flatten[Abs[ Differences/@ Thread[{fir, las}]]]-1/.{-1->0}] (* Harvey P. Dale, Jun 11 2014 *)
CROSSREFS
KEYWORD
nonn
AUTHOR
Michel Lagneau, Jan 10 2012
STATUS
approved