A084954 Initial prime of a prime chain of length n under the iteration x->2x+3.

2, 2, 2, 2, 47, 47, 6047, 477727, 30596497, 3388516667, 340746580567, 1763093883977, 773521306107547, 1142275515892937

Offset

1,1

Comments

This is a special case of prime chains generated by f(x) = cx + d.

Is it smallest initial prime of a prime chain of length n under the iteration x->2x+3, or not? At least up to 3388516667 it is the smallest one. - Zak Seidov, Dec 20 2013

Links

Table of n, a(n) for n=1..14.

D. H. Lehmer, On certain chains of primes, Proc. London Math. Soc. (3) 14a 1965 183-186.

Example

a(3) = 2 since 2, 2*2+3=7 and 2*7+3=17 are primes.

Crossrefs

Cf. A057330, A057331, A083388, A084955, A084956, A084957, A084958, A084959, A084960, A084961, A128509, A134701, A134702.

Sequence in context: A289087 A154288 A225057 * A226281 A217993 A049300

Adjacent sequences: A084951 A084952 A084953 * A084955 A084956 A084957

Keyword

nonn,more

Author

W. Edwin Clark, Jun 14 2003

Extensions

More terms from Don Reble, Nov 07 2007

Status

approved