1,1

2*(2^2-1)*(2^3-1) - 1 = 41 prime so k(1)=2

2*(2^3-1)*(2^5-1) - 1 = 433 prime so k(2)=2

Sequence in context: A099640 A140283 A067097 this_sequence A095855 A147975 A083148

Adjacent sequences: A098912 A098913 A098914 this_sequence A098916 A098917 A098918

nonn

Pierre CAMI (pierrecami(AT)tele2.fr), Oct 17 2004