OFFSET
1,1
LINKS
Harvey P. Dale, Table of n, a(n) for n = 1..1000
EXAMPLE
If n=3, then (p(3)+r(3))/3 = (5+4)/3 = 3 = a(1).
If n=15, then (p(15)+r(15))/3 = (47+22)/3 = 23 = a(2).
If n=18, then (p(18)+r(18))/3 = (61+26)/3 = 29 = a(3).
If n=22, then (p(22)+r(22))/3 = (79+32)/3 = 37 = a(4).
If n=24, then (p(24)+r(24))/3 = (89+34)/3 = 41 = a(5), etc.
MATHEMATICA
Module[{nn=5000, pr, comp, len}, pr=Prime[Range[PrimePi[nn]]]; comp = Complement[ Range[0, nn], pr]; len = Min[ Length[pr], Length[comp]]; Select[Total[#]/3&/@Thread[ {Take[pr, len], Take[comp, len]}], PrimeQ]] (* Harvey P. Dale, Dec 04 2012 *)
CROSSREFS
KEYWORD
nonn
AUTHOR
Juri-Stepan Gerasimov, Sep 19 2008
EXTENSIONS
167 inserted, 347 inserted and extended by R. J. Mathar, Nov 03 2008
STATUS
approved