A107695 - OEIS

%I #11 Sep 08 2022 08:45:18

%S 19,191,313,331,911,11119,111119,111191,113131,131113,131311,911111,

%T 1131113,1131131,1311131,1311311,3111131,3113111,11111119,11111911,

%U 11911111,111111313,111111331,111113113,111113131,111131131,111133111

%N Primes with digital product = 9.

%H Harvey P. Dale, <a href="/A107695/b107695.txt">Table of n, a(n) for n = 1..9000</a>

%t Union[ Flatten[ Table[ Select[ Sort[ FromDigits /@ Join[ Permutations[ Flatten[{9, Table[1, {n}]}]], Permutations[ Flatten[{3, 3, Table[1, {n - 1}]}]]]], PrimeQ[ # ] & ], {n, 0, 8}]]]

%t Select[Prime[Range[3 10^6]], Times@@IntegerDigits[#] == 9 &] (* _Vincenzo Librandi_, Jul 27 2016 *)

%o (Magma) [p: p in PrimesUpTo(3*10^7) | &*Intseq(p) eq 9]; // _Vincenzo Librandi_, Jul 27 2016

%Y Cf. A004022, A107612, A107689, A107690, A107691, A107692, A107693, A107694, A107696, A107697, A107698.

%K base,nonn

%O 1,1

%A _Zak Seidov_ and _Robert G. Wilson v_, May 20 2005