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A112009
Numbers n with even length such that phi(n)=d_1^d_2*d_3^d_4*...* d_(k-1)^d_k where d_1 d_2 ... d_k is the decimal expansion of n.
3
113724, 116680, 126620, 176453, 236520, 12146841, 12514635, 13334445, 13469331, 13813728, 16473510, 18259344, 20116537, 20119347, 21324832, 23336066, 27923616, 30352728, 34425425, 35424571, 36311184, 37837170, 39171345, 43362816, 45429360, 45449216, 45916416, 46544032, 50713684, 50816880, 61642672, 62193744, 62226711, 62263890, 62288272, 64245272, 64808352, 64832560, 66707233, 66807126, 66827180, 81913446, 84943040
OFFSET
1,1
EXAMPLE
27923616 is in the sequence because phi(27923616)=2^7*9^2*3^6*1^6.
11600069 and 23635500 are not members, since 0^0 is undefined.
MATHEMATICA
Do[h = IntegerDigits[n]; k = Length[h]; If[EvenQ[k] && Select[ Range[k/2], h[[2#-1]] == 0 &] == {} && EulerPhi[n]==Product[ h[[2j-1]]^h[[2j]], {j, k/2}], Print[n]], {n, 30000000}]
CROSSREFS
KEYWORD
base,nonn
AUTHOR
Farideh Firoozbakht, Aug 26 2005
EXTENSIONS
Edited by N. J. A. Sloane, Apr 02 2009
More terms from Max Alekseyev, Oct 16 2012
STATUS
approved