OFFSET
1,1
FORMULA
EXAMPLE
The averages of twin prime pairs in A014574 are 4, 6, 12, 18, 30, 42, ...
The sequence contains gcd(4, 6) = 2, gcd(6, 12) = 6, gcd(12,18) = 6, gcd(18,30) = 6, etc.
MAPLE
MATHEMATICA
GCD[a = Select[Range[5, 998], PrimeQ[ # - 1] && PrimeQ[ # + 1] &], b = Select[Range[4, 881], PrimeQ[ # - 1] && PrimeQ[ # + 1] &]]
CROSSREFS
KEYWORD
nonn,easy
AUTHOR
Vladimir Joseph Stephan Orlovsky, Apr 22 2008
EXTENSIONS
More terms from R. J. Mathar, May 05 2008
STATUS
approved