A082714 - OEIS

A082714

Numbers n such that 2*(10^n-1)/3+(10^(n-1)+1) or (69*10^(n-1)+3)/9 is a plateau or depression prime.

5, 7, 55, 97, 455, 575, 3385, 11441, 12625, 19447, 35461, 81215, 95327

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OFFSET

1,1

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

EXAMPLE

7 is a term because 2*(10^7-1)/3+(10^6+1) = 7666667.

CROSSREFS

KEYWORD

nonn,base,more

AUTHOR

EXTENSIONS

35461 from Herman Jamke (hermanjamke(AT)fastmail.fm), Jan 02 2008

Added two more terms from PDP table, by Patrick De Geest, Nov 04 2014

Edited by Ray Chandler, Nov 05 2014

Name clarified by Michel Marcus, Mar 27 2020

STATUS

approved