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, 391230854658184967

Offset: 1

Author

W. Edwin Clark, Jun 14 2003

Keywords

• nonn
• more

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

Examples

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

Links

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

Crossrefs

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

Extensions

More terms from Don Reble, Nov 07 2007

a(15) from Bert Dobbelaere, Jun 01 2025