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A031979 Smallest digit of n concatenated with largest digit of n is prime. 0

%I #7 Dec 15 2017 17:34:48

%S 11,13,17,19,20,23,29,30,31,32,37,47,50,59,67,70,71,73,74,76,79,89,91,

%T 92,95,97,98,102,103,105,107,111,113,117,119,120,123,127,129,130,131,

%U 132,133,137,139,147,149,150,157,159,167,169,170,171,172,173,174,175

%N Smallest digit of n concatenated with largest digit of n is prime.

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

%Y Cf. A054054, A054055.

%K base,nonn

%O 1,1

%A _Jason Earls_, Jun 25 2003

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Last modified March 28 04:05 EDT 2024. Contains 371235 sequences. (Running on oeis4.)