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A082703 Plateau and depression primes of the form (10^a(n)-1)-8*(10^[ a(n)-1 ]+1) or (18*10^[ a(n)-1 ]-81)/9. 1
3, 5, 9, 41, 87, 201, 731, 1461, 23673, 28631 (list; graph; refs; listen; history; internal format)
OFFSET

0,1

COMMENTS

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 199...991.

EXAMPLE

a(n)=9 -> (10^9-1)-8*(10^8+1) = 199999991.

CROSSREFS

Cf. A082697 up to A082720.

Sequence in context: A082711 A013622 A027715 * A125708 A055289 A124974

Adjacent sequences:  A082700 A082701 A082702 * A082704 A082705 A082706

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 February 14 04:29 EST 2012. Contains 205570 sequences.