A133753 Larger of emirps (pairs) with only prime digits (A128388).
73, 733, 3733, 7253, 7523, 7757, 33223, 35323, 72253, 72353, 73327, 73523, 73553, 75223, 75253, 77237, 77323, 77527, 77557, 333323, 352333, 355723, 375223, 375233, 375553, 722333, 727327, 733333, 735733, 737353, 737753, 737773, 753373, 753527, 772273, 773273, 775757, 777353, 777373
Offset: 1
Links
- Harvey P. Dale, Table of n, a(n) for n = 1..1000
Programs
-
Maple
read(transforms) : isA006567 := proc(n) local digs,prev ; if isprime(n) then prev := digrev(n) ; if n <> prev and isprime(prev) then true ; else false ; fi ; else false ; fi ; end: isA128388 := proc(n) local digs ; if isA006567(n) then digs := convert(convert(n,base,10),set) ; if digs minus {2,3,5,7} = {} then true ; else false ; fi ; else false ; fi ; end: isA133753 := proc(n) if isA128388(n) then if digrev(n) < n then true; else false ; fi ; else false ; fi ; end: for n from 1 to 200000 do p := ithprime(n) ; if isA133753(p) then printf("%d, ",p) ; fi ; od: # R. J. Mathar, Jan 30 2008
-
Mathematica
Select[(Table[(Sort/@Select[{#,IntegerReverse[#]}&/@Select[FromDigits/@Tuples[ {2,3,5,7},n],PrimeQ],AllTrue[#,PrimeQ]&])[[;;,2]]//Union,{n,2,6}]//Flatten//Union),!PalindromeQ[#]&] (* Harvey P. Dale, Sep 15 2024 *)
Formula
Extensions
Extended by Ray Chandler and R. J. Mathar, Jan 30 2008