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A051832 Numbers k such that (2*10^(5*k) - 10^(4*k) + 2*10^(3*k) + 10^(2*k) + 10^k + 1)/3 is prime. 10
0, 1, 7, 133 (list; graph; refs; listen; history; text; internal format)
OFFSET
1,3
COMMENTS
The Baxter-Hickerson function provides a number whose cube lacks zeros.
The next term is > 4400. - Jason Earls, Sep 10 2005
The next term is > 20000 (found using pfgw64). - Patrick De Geest, Jul 22 2012
LINKS
Ed Pegg, Jr., Fun with numbers.
Eric Weisstein's World of Mathematics, Baxter-Hickerson Function.
MAPLE
f := n->(2*10^(5*n) - 10^(4*n) + 2*10^(3*n) + 10^(2*n) + 10^n + 1)/3;
PROG
(PARI) is(n)=isprime((2*10^(5*n)-10^(4*n)+2*10^(3*n)+10^(2*n)+10^n+1)/3) \\ Charles R Greathouse IV, Feb 17 2017
CROSSREFS
Sequence in context: A220321 A247597 A305955 * A103050 A110111 A245318
KEYWORD
hard,nonn
AUTHOR
G. L. Honaker, Jr., Dec 11 1999
STATUS
approved

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Last modified April 25 05:56 EDT 2024. Contains 371964 sequences. (Running on oeis4.)