OFFSET
1,2
EXAMPLE
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.
PROG
(PARI) P=7; for(i=1, 20, k=0; while(!ispseudoprime(t=k++*P*(k*P-1)-1), ); P=t; print1(k", ")) \\ Michel Marcus, Sep 16 2019 ; after A141240
CROSSREFS
KEYWORD
nonn,more
AUTHOR
Pierre CAMI, Jun 16 2008
STATUS
approved