

A068827


a(1) = 2; for n > 1, a(n) is the smallest prime > a(n1) such that each successive digit in the concatenation of terms (that does not follow 9) is greater than the previous digit.


1



2, 3, 5, 7, 89, 127, 919, 1237, 8923, 8929, 8969, 12347, 89123, 89137, 89189, 89237, 89269, 89293, 89393, 89459, 89491, 89567, 89591, 89597, 89689, 89797, 89891, 89897, 91237, 91249, 123457, 891239, 891349, 891379, 891389, 891391
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OFFSET

1,1


LINKS

Zak Seidov, Table of n, a(n) for n=1..1001
R. J. Mathar, Maple program.
Hugo van der Sanden, Perl program.


EXAMPLE

From Petros Hadjicostas, Jun 06 2020: (Start)
a(4) = 7 because 7 is the smallest prime such that, when it is concatenated to 235, we get 2357 and each successive digit is greater than the previous one.
a(5) = 89 because 89 is the smallest prime such that, when it is concatenated to 2357, we get 235789 and each successive digit is greater than the previous one.
a(6) = 127 because 127 is the smallest prime such that, when it is concatenated to 235789, we get 235789127 and each successive digit that does not follow 9 is greater than the previous one. (End)


CROSSREFS

Sequence in context: A356981 A070275 A171042 * A289755 A318202 A076406
Adjacent sequences: A068824 A068825 A068826 * A068828 A068829 A068830


KEYWORD

nonn,base


AUTHOR

Amarnath Murthy, Mar 08 2002


EXTENSIONS

Edited by Larry Reeves (larryr(AT)acm.org), Jan 13 2003
Corrected and extended by Franklin T. AdamsWatters, R. J. Mathar, Zak Seidov and Hugo van der Sanden, May 12 2010
Name edited by Petros Hadjicostas, Jun 06 2020


STATUS

approved



