OFFSET
1,1
EXAMPLE
33452293 is in the sequence because phi(33452293)=phi(3^3*4^5*2^2*9^3).
MATHEMATICA
Do[h = IntegerDigits[n]; k = Length[h]; If[EvenQ[k] && Select[ Range[k/2], h[[2#-1]] == 0 &] == {} && EulerPhi[n]==EulerPhi [Product[h[[2j-1]]^h[[2j]], {j, k/2}], Print[n]], {n, 31000000}]
epQ[n_]:=Module[{idn=IntegerDigits[n]}, EvenQ[Length[idn]]&& FreeQ[ Take[ idn, {1, -1, 2}], 0] && EulerPhi[n] == EulerPhi[Times@@(#[[1]]^#[[2]]&/@ Partition[ idn, 2])]]; Join[Select[Range[10, 99], epQ], Select[Range[ 1000, 9999], epQ], Select[Range[100000, 999999], epQ], Select[Range[ 10000000, 44999999], epQ]] (* Harvey P. Dale, Feb 24 2016 *)
CROSSREFS
KEYWORD
base,nonn
AUTHOR
Farideh Firoozbakht, Aug 26 2005
EXTENSIONS
More terms from Max Alekseyev, Oct 16 2012
STATUS
approved