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A031979 Smallest digit of n concatenated with largest digit of n is prime. 1
11, 13, 17, 19, 20, 23, 29, 30, 31, 32, 37, 47, 50, 59, 67, 70, 71, 73, 74, 76, 79, 89, 91, 92, 95, 97, 98, 102, 103, 105, 107, 111, 113, 117, 119, 120, 123, 127, 129, 130, 131, 132, 133, 137, 139, 147, 149, 150, 157, 159, 167, 169, 170, 171, 172, 173, 174, 175 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,1

LINKS

Table of n, a(n) for n=1..58.

EXAMPLE

a(5)=20 because 2 is prime. a(1300)=3295 because 29 is prime.

CROSSREFS

Cf. A054054, A054055.

Sequence in context: A068569 A124176 A210757 * A055239 A138708 A061116

Adjacent sequences:  A031976 A031977 A031978 * A031980 A031981 A031982

KEYWORD

base,nonn

AUTHOR

Jason Earls, Jun 25 2003

STATUS

approved

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Last modified November 21 01:33 EST 2019. Contains 329349 sequences. (Running on oeis4.)