login
The OEIS Foundation is supported by donations from users of the OEIS and by a grant from the Simons Foundation.

 

Logo


Hints
(Greetings from The On-Line Encyclopedia of Integer Sequences!)
A107694 Primes with digital product = 8. 11

%I

%S 181,241,421,811,1181,1811,2141,2221,2411,4211,8111,21221,141121,

%T 142111,411211,1111181,1112141,1121221,1211141,1211411,1212121,

%U 2111411,2121121,2211211,2221111,2411111,4121111,4211111,11221211,12111221,12121121

%N Primes with digital product = 8.

%t Union[ Flatten[ Table[ Select[ Sort[ FromDigits /@ Join[ Permutations[ Flatten[{8, Table[1, {n}]}]], Permutations[ Flatten[{2, 4, Table[1, {n - 1}]}]], Permutations[ Flatten[{2, 2, 2, Table[1, {n - 2}]}] ]]], PrimeQ[ # ] & ], {n, 0, 7}]]]

%t Select[Prime[Range[3 10^6]], Times@@IntegerDigits[#] == 8 &] (* _Vincenzo Librandi_, Jul 27 2016 *)

%o (MAGMA) [p: p in PrimesUpTo(3*10^7) | &*Intseq(p) eq 8]; // _Vincenzo Librandi_, Jul 27 2016

%Y Cf. A004022, A107612, A107689, A107690, A107691, A107692, A107693, A107695, A107696, A107697, A107698.

%K base,nonn

%O 1,1

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

Lookup | Welcome | Wiki | Register | Music | Plot 2 | Demos | Index | Browse | More | WebCam
Contribute new seq. or comment | Format | Style Sheet | Transforms | Superseeker | Recent
The OEIS Community | Maintained by The OEIS Foundation Inc.

License Agreements, Terms of Use, Privacy Policy. .

Last modified January 24 19:19 EST 2020. Contains 331211 sequences. (Running on oeis4.)