A078265 Integer part of the geometric mean of all the distinct numbers formed by permuting the digits of concatenation of numbers from 1 to n.
1, 15, 207, 2544, 30091, 347096, 3931343, 43906441, 484912312, 5306957044
Offset: 1
Examples
a(3) = floor((123*132*213*231*312*321)^(1/6)) = floor(207.581...) = 207. a(4) = floor((1234*1243*1324*1342*1423*1432*...*4312*4321)^(1/24)) = floor(2544.967...) = 2544.
Programs
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Mathematica
a[n_] := Floor[ (Times @@ FromDigits /@ Permutations[Range[n]])^(1/n!) ]; Table[a[n], {n, 1, 10}] (* Ryan Propper, Jul 21 2006 *)
Extensions
More terms from Ryan Propper, Jul 21 2006
Comments