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A082713 Plateau and depression primes of the form 5*(10^a(n)-1)/9+2*(10^[ a(n)-1 ]+1) or (68*10^[ a(n)-1 ]+13)/9. +0
2
3, 5, 11, 21, 23, 59, 75, 83, 209, 351, 423, 3813, 3983, 20925, 23787, 38853 (list; graph; listen)
OFFSET

0,1

COMMENT

Prime versus probable prime status and proofs are given in the author's table.

REFERENCES

C. Caldwell and H. Dubner, "Journal of Recreational Mathematics", Volume 28, No. 1, 1996-97, pp. 1-9.

LINKS

P. De Geest, PDP Reference Table

Makoto Kamada, Factorizations of 755...557.

EXAMPLE

a(n)=21 -> 5*(10^21-1)/9+2*(10^20+1) = 755555555555555555557.

CROSSREFS

Cf. A082697 up to A082720.

Sequence in context: A058932 A118037 A094588 this_sequence A074710 A057460 A045515

Adjacent sequences: A082710 A082711 A082712 this_sequence A082714 A082715 A082716

KEYWORD

nonn,base

AUTHOR

Patrick De Geest (pdg(AT)worldofnumbers.com), Apr 13 2003.

EXTENSIONS

More terms from Herman Jamke (hermanjamke(AT)fastmail.fm), Jan 02 2008

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Last modified September 8 08:06 EDT 2008. Contains 143486 sequences.


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