login
The OEIS Foundation is supported by donations from users of the OEIS and by a grant from the Simons Foundation.

 

Logo


Hints
(Greetings from The On-Line Encyclopedia of Integer Sequences!)
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 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,2

COMMENTS

a(n) is divisible by 3.

LINKS

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

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

Cf. A046933, A063091, A167132, A204100.

Sequence in context: A098355 A183429 A107443 * A062234 A168329 A161828

Adjacent sequences:  A204096 A204097 A204098 * A204100 A204101 A204102

KEYWORD

nonn

AUTHOR

Michel Lagneau, Jan 10 2012

STATUS

approved

Lookup | Welcome | Wiki | Register | Music | Plot 2 | Demos | Index | Browse | More | WebCam
Contribute new seq. or comment | Format | Style Sheet | Transforms | Superseeker | Recent
The OEIS Community | Maintained by The OEIS Foundation Inc.

License Agreements, Terms of Use, Privacy Policy. .

Last modified August 13 06:22 EDT 2020. Contains 336442 sequences. (Running on oeis4.)