OFFSET
1,1
COMMENTS
prime(11+3) + prime(11-3) = 2*prime(11); therefore prime(11) = 31 is in the sequence.
MATHEMATICA
a = {}; For[k = 3, k < 100, k++, For[n = 1, n < k - 1, n++, If[(Prime[k + n] + Prime[k - n])/2 == Prime[k], AppendTo[a, Prime[k]]]]]; Union[a, a]
CROSSREFS
KEYWORD
nonn
AUTHOR
Artur Jasinski, Dec 23 2006
EXTENSIONS
Edited, corrected and extended by Stefan Steinerberger, Jul 31 2007
STATUS
approved