

A005603


Chains of length n of nearly doubled primes.
(Formerly M4766)


12



11, 7, 2, 2131, 1531, 385591, 16651, 15514861, 857095381, 205528443121, 1389122693971, 216857744866621, 758083947856951, 107588900851484911, 69257563144280941
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OFFSET

1,1


COMMENTS

Complete Cunningham chain of the second kind.


REFERENCES

N. J. A. Sloane and Simon Plouffe, The Encyclopedia of Integer Sequences, Academic Press, 1995 (includes this sequence).


LINKS

Table of n, a(n) for n=1..15.
G. Löh, Long chains of nearly doubled primes, Math. Comp., 53 (1989), 751759.
C. K. Caldwell, Cunningham chain.


CROSSREFS

A064812 is a better version.
Cf. (A005382 and A005383), A057326, A057327, A057328, A057329, A057330, A005602.
Sequence in context: A241308 A038320 A010185 * A109828 A048981 A132361
Adjacent sequences: A005600 A005601 A005602 * A005604 A005605 A005606


KEYWORD

nonn


AUTHOR

N. J. A. Sloane.


EXTENSIONS

6th term corrected from 385591 on Feb 23 1995, at Robert G. Wilson v's suggestion
a(14) and a(15) found by Paul Jobling (Paul.Jobling(AT)WhiteCross.com) [Oct 23 2000]
a(6) reverted to original value by Sean A. Irvine, Jul 10 2016


STATUS

approved



