A086554 a(1) = 1; for n>1, a(n) = smallest number not included earlier such that each P+1 is prime, where P is the product of an (n-1)-set from the previous n terms.

1, 2, 6, 23, 370, 1056, 36695, 491942, 23005823

Offset

1,2

Comments

Conjecture: sequence is finite.

No more terms < 166890000. - David Wasserman, Apr 19 2005

Links

Table of n, a(n) for n=1..9.

Example

a(4) = 23 as 1*2*6+1, 2*6*23+1, 1*6*23+1 and 1*2*23+1 (i.e. 13, 277, 139 and 47) all are primes.

Crossrefs

Sequence in context: A364791 A020122 A327426 * A213324 A007672 A322255

Adjacent sequences: A086551 A086552 A086553 * A086555 A086556 A086557

Keyword

nonn

Author

Amarnath Murthy, Aug 29 2003

Extensions

Corrected and extended by David Wasserman, Apr 19 2005

Status

approved