A143181 Sequence of a(n) such that : define p(0)=2 the first prime, then p(n+1)=least prime p of the form a(n)*p(n)*(a(n)*p(n)+1)-1 with a twin prime p+2.

1, 1, 7, 135, 549, 7209, 1741, 4197, 172434, 2638147

Offset

1,3

Links

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

Example

1*2*(1*2+1)-1=5, 7 twin prime so a(1)=1
1*5*(1*5+1)-1=29, 31 twin prime so a(2)=1

Crossrefs

Cf. A120393.

Sequence in context: A119670 A003374 A001533 * A183478 A292395 A081793

Adjacent sequences: A143178 A143179 A143180 * A143182 A143183 A143184

Keyword

more,nonn

Author

Pierre CAMI, Jul 28 2008

Status

approved