1,2

1*7*7-1*7-1=41 prime so k(1)=1 P(1)=41

1*41*(1*41-1)-1=1639 composite

2*41*(2*41-1)-1=6641 composite

3*41*(3*41-1)-1=15005 composite

4*41*(4*41-1)-1=26731 prime so k(2)=4 P(2)=26731

1*26731*(1*26731-1)-1=714519629 prime so k(3)=1 P(3)=714519629

Cf. A141234 A141235 A141236 A141237 A141238 A141239 A141240.

Sequence in context: A113355 A077102 A057968 this_sequence A055139 A128041 A144885

Adjacent sequences: A141230 A141231 A141232 this_sequence A141234 A141235 A141236

nonn

Pierre CAMI (pierrecami(AT)tele2.fr), Jun 16 2008