A133753 - OEIS

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

(list; graph; refs; listen; history; text; internal format)

OFFSET

1,1

LINKS

Harvey P. Dale, Table of n, a(n) for n = 1..1000

FORMULA

{p in A128388: p> A004086(p)}. - R. J. Mathar, Jan 30 2008

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 *)

CROSSREFS

Cf. A128388, A133554.

Sequence in context: A167187 A177095 A321422 * A177514 A137835 A063784

Adjacent sequences: A133750 A133751 A133752 * A133754 A133755 A133756

KEYWORD

nonn,base

AUTHOR

Lekraj Beedassy, Jan 21 2008

EXTENSIONS

Extended by Ray Chandler and R. J. Mathar, Jan 30 2008

STATUS

approved