OFFSET
0,3
COMMENTS
(2^2)*3-1=11, (2^3)*3-1=23 and (2^4)*3-1=47 are primes so 3 is the third entry.
For every x in A001122, the x-th term of this sequence and every succeeding term is divisible by x. For example 3 divides the 3rd and every succeeding term, 5 divides the 5th and every succeeding term.
The sequences of primes generated by these numbers are a type of Cunningham chain of the first kind (CC1). Since the longest known CC1 chain is of length 16, the next terms are currently unknown. - Douglas Stones (dssto1(AT)student.monash.edu.au), Mar 16 2005
LINKS
Paul Jobling, NewPGen
G. Loeh, Long chains of nearly doubled primes, Mathematics of Computation, Vol. 53, No. 188, Oct 1989, pp. 751-759.
CROSSREFS
KEYWORD
hard,nonn
AUTHOR
Douglas Stones (dssto1(AT)student.monash.edu.au), Dec 16 2004; revised Dec 31 2004
EXTENSIONS
More terms from Douglas Stones (dssto1(AT)student.monash.edu.au), Mar 16 2005
STATUS
approved