A141235 Sequence of k such that starting with P(0)=13 then k(n)*P(n-1)*(k(n)*P(n-1)-1)-1 is the least prime = P(n).

3, 2, 15, 8, 11, 70, 271, 429, 189, 109

Offset

1,1

Links

Table of n, a(n) for n=1..10.

Example

1*13*(1*13-1)-1=155 composite,
2*13*(2*13-1)-1=649 composite,
3*13*(3*13-1)-1=1481 prime so a(1)=3 and P(1)=1481.

Prog

(PARI) P=13; for(i=1, 20, k=0; while(!ispseudoprime(t=k++*P*(k*P-1)-1), ); P=t; print1(k", ")) \\ Michel Marcus, Sep 24 2019

Crossrefs

Cf. A141233, A141234, A141236, A141237, A141238, A141239, A141240.

Sequence in context: A072346 A334865 A103236 * A199167 A218969 A345291

Adjacent sequences: A141232 A141233 A141234 * A141236 A141237 A141238

Keyword

nonn,more

Author

Pierre CAMI, Jun 16 2008

Extensions

a(9)-a(10) from Michel Marcus, Sep 24 2019

Status

approved