A068827 a(1) = 2; for n > 1, a(n) is the smallest prime > a(n-1) such that each successive digit in the concatenation of terms (that does not follow 9) is greater than the previous digit.

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

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. Adams-Watters, R. J. Mathar, Zak Seidov and Hugo van der Sanden, May 12 2010

Name edited by Petros Hadjicostas, Jun 06 2020

Status

approved