1,1

a(3)=11=4*3-1, a(4)=13=4*3+1

i:=1:for k from 1 to 600 do if isprime(4*k-1) and isprime(4*k+1) then a[i]:=4*k-1:a[i+1]:=4*k+1: i:=i+2 fi od: seq(a[n], n=1..i-1);

Cf. A001097.

Adjacent sequences: A122561 A122562 A122563 this_sequence A122565 A122566 A122567

Sequence in context: A089251 A006794 A032457 this_sequence A058595 A086284 A136500

nonn

Miklos Kristof (kristmikl(AT)freemail.hu), Sep 21 2006