"Jon Perry" <perry at globalnet.co.uk> wrote: > I don't understand the defintion. > > Jon Perry A001359 (greater of twin primes) begins: 5,7,13,19,31,43,61,73,103,... A079329 begins: 6,10,16,25,37,52,67,88,106,... avg(5,7)=6 avg(7,13)=10 avg(13,19)=16 ... Christian