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Numbers n such that n * (product of digits of n) + 1 is prime.
1

%I #21 Aug 14 2013 12:23:58

%S 1,2,4,6,16,21,22,23,24,25,26,27,28,29,32,34,42,52,61,65,66,69,72,83,

%T 84,86,92,98,114,123,134,138,161,165,169,176,186,192,213,216,219,222,

%U 223,228,239,249,253,256,258,259,265,273,286,289,292,293,294,297

%N Numbers n such that n * (product of digits of n) + 1 is prime.

%H Jayanta Basu, <a href="/A228119/b228119.txt">Table of n, a(n) for n = 1..10000</a>

%e 16 is a member since 16 * (product of digits of 16) + 1 = 16*6 + 1 = 97 is a prime.

%t Select[Range[300], PrimeQ[(#*Times @@ IntegerDigits[#]) + 1] &]

%Y Cf. A000040, A007954.

%K nonn,base

%O 1,2

%A _Jayanta Basu_, Aug 14 2013