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A070955 Numbers n such that n concatenated with n-1 0's and its reversal is prime. 0
1, 122, 346, 1454, 3526, 7408 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,2

COMMENTS

a(2) and a(3) certified prime with Primo. a(4) is a probable prime.

a(7) > 10^4.

LINKS

Table of n, a(n) for n=1..6.

EXAMPLE

a(2)=122 because 12200...(121 zeros)...000221 is prime.

CROSSREFS

Sequence in context: A004925 A276303 A224598 * A195856 A116216 A203805

Adjacent sequences:  A070952 A070953 A070954 * A070956 A070957 A070958

KEYWORD

base,more,nonn

AUTHOR

Jason Earls, May 25 2002

EXTENSIONS

a(5), a(6) from Max Alekseyev, May 21 2011

STATUS

approved

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Last modified November 20 10:09 EST 2019. Contains 329334 sequences. (Running on oeis4.)