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Revision History for A111471

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a(1) = 1; for n>1, a(n) = least k such that concatenation of n copies of k with all previous concatenations gives a prime.
(history; published version)

#4 by N. J. A. Sloane at Thu Dec 05 19:57:05 EST 2013

AUTHOR

_Amarnath Murthy (amarnath_murthy(AT)yahoo.com), _, Aug 05 2005

Discussion

Thu Dec 05

19:57

OEIS Server: https://oeis.org/edit/global/2075

#3 by Russ Cox at Fri Mar 30 17:34:56 EDT 2012

EXTENSIONS

More terms from _Donovan Johnson (donovan.johnson(AT)yahoo.com), _, Feb 26 2008

Discussion

Fri Mar 30

17:34

OEIS Server: https://oeis.org/edit/global/163

#2 by N. J. A. Sloane at Sun Jun 29 03:00:00 EDT 2008

NAME

a(1) = 1, ; for n>1, a(n) = least k such that concatenation of n copies of k with all previous concatenation concatenations gives a prime.

DATA

1, 9, 7, 3, 29, 19, 21, 121, 7, 211, 207, 11, 221, 347, 99, 123, 303, 189, 1131, 1179, 2069, 3437, 2211, 211, 3169, 1551, 3493, 7433, 6939, 1053, 1537, 9417, 4491, 1257, 19693, 9, 1653, 3329, 317, 8667, 799, 1053, 5617, 6049, 1721, 24871, 2751, 737, 3303, 29079

EXAMPLE

199, 199777, 1997773333,1977733332929292929 19977733332929292929 are all primeprimes.

KEYWORD

base,hard,more,nonn,new

base,nonn

EXTENSIONS

More terms from Donovan Johnson (donovan.johnson(AT)yahoo.com), Feb 26 2008

#1 by N. J. A. Sloane at Wed Sep 21 03:00:00 EDT 2005

NAME

a(1) = 1, a(n) = least k such that concatenation of n copies of k with all previous concatenation gives a prime.

DATA

1, 9, 7, 3, 29

OFFSET

1,2

EXAMPLE

199,199777,1997773333,1977733332929292929 are all prime.

CROSSREFS

Cf. A111472.

KEYWORD

base,hard,more,nonn

AUTHOR

Amarnath Murthy (amarnath_murthy(AT)yahoo.com), Aug 05 2005

STATUS

approved