OFFSET
1,1
COMMENTS
Sum of two consecutive primes = arithmetic mean of twin primes.
LINKS
Vincenzo Librandi, Table of n, a(n) for n = 1..1000
EXAMPLE
5+7=12-+1 primes, 7+11=18-+1 primes, 13+17-+1 primes, ...
MAPLE
t1:=[]; for n from 2 to 1000 do p:=ithprime(n); q:=prevprime(p);
if isprime(p+q-1) and isprime(p+q+1) then t1:=[op(t1), p]; fi; od: t1; # N. J. A. Sloane, Dec 24 2012
MATHEMATICA
lst={}; Do[p0=Prime[n]; p1=Prime[n+1]; a=p0+p1; If[PrimeQ[a-1] && PrimeQ[a+1], AppendTo[lst, p1]], {n, 1000}]; lst
CROSSREFS
KEYWORD
nonn
AUTHOR
Vladimir Joseph Stephan Orlovsky, Mar 16 2009
STATUS
approved