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A075611 a(1) = 1, a(n) = smallest number > a(n-1) such that concatenation a(k) a(n) is prime for all k = 1 to n-1. Stop if no such number exists. 2
1, 3, 7, 73, 433, 607, 13381, 37279, 4800307, 1281054613 (list; graph; refs; listen; history; internal format)
OFFSET

1,2

COMMENTS

The sequence is probably finite.

EXAMPLE

a(5)=433 since 1433, 3433, 7433 and 73433 are all primes and for every 73<x<433, at least one of 1x, 3x, 7x, 73x is not prime.

CROSSREFS

Sequence in context: A078552 A091259 A088647 * A191485 A119572 A172995

Adjacent sequences:  A075608 A075609 A075610 * A075612 A075613 A075614

KEYWORD

base,more,nonn

AUTHOR

Amarnath Murthy (amarnath_murthy(AT)yahoo.com), Sep 28 2002

EXTENSIONS

Corrected and extended by Giovanni Resta (g.resta(AT)iit.cnr.it), Jun 18 2003

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Last modified February 14 03:37 EST 2012. Contains 205570 sequences.