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A031979 Smallest digit of n concatenated with largest digit of n is prime. 0
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
EXAMPLE
a(5)=20 because 2 is prime. a(1300)=3295 because 29 is prime.
CROSSREFS
Sequence in context: A068569 A124176 A210757 * A055239 A352154 A138708
KEYWORD
base,nonn
AUTHOR
Jason Earls, Jun 25 2003
STATUS
approved

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Last modified May 23 18:34 EDT 2024. Contains 372765 sequences. (Running on oeis4.)