OFFSET
1,3
COMMENTS
Appears to be the partial sums of A160273 which are the successive differences (divided by 3) of the average of twin prime pairs divided by 2 (A040040). - Stephen Crowley, May 24 2009
LINKS
Vincenzo Librandi, Table of n, a(n) for n = 1..2000
EXAMPLE
For n = 0, 6*n+5 = 5 and 6*n+7 = 7 are twin primes;
for n = 99, 6*n+5 = 599 and 6*n+7 = 601 are twin primes.
MAPLE
ZL := []; for p to 1000000 do if `and`(isprime(p), isprime(p+2)) then ZL := [op(ZL), ((p+2)^2-p^2)*(1/8)] end if end do; A160273 := [seq((ZL[i+1]-ZL[i])*(1/3), i = 2 .. nops(ZL)-1)]: ListTools[PartialSums]( A160273 ); # Stephen Crowley, May 24 2009
MATHEMATICA
Select[Range[0, 350], PrimeQ[6 # + 5]&&PrimeQ[6 # + 7]&] (* Vincenzo Librandi, Apr 04 2013 *)
PROG
(Magma) [ n: n in [0..335] | IsPrime(6*n+5) and IsPrime(6*n+7) ];
CROSSREFS
KEYWORD
nonn,easy
AUTHOR
Vincenzo Librandi, Dec 20 2008
EXTENSIONS
Edited and extended by Klaus Brockhaus, Dec 26 2008
STATUS
approved