A119845 Positions where new distinct values appear in A119842.
1, 6, 36, 72, 120, 144, 180, 192, 288, 420, 432, 480, 576, 720, 900, 1080, 1152, 1296, 1680, 1728, 1800, 1920, 2304, 2520, 2592, 2880, 3072, 3600, 4320, 4608, 5184, 6300, 6480, 6720, 6912, 7200, 7680, 9216, 9240
Offset: 1
Keywords
Programs
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Mathematica
b[s_, t_] := b[s, t] = If[Length[s] < 1, 1, Sum[If[Mod[PrimeOmega[x], 2] == 1 - t && Length[Select[s, Mod[#, x] == 0 &]] == 1, b[s~Complement~{x}, 1 - t], 0], {x, s}]]; a[n_] := a[n] = Module[{l, m}, l = Sort[ FactorInteger[n], #1[[2]] > #2[[2]] &]; m = Product[Prime[i]^l[[i]][[2]], {i, 1, Length[l]}]; b[Divisors[m][[2 ;; -2]], Mod[PrimeOmega[m], 2]]]; Join[{1}, Reap[For[ k = 2, k < 10^4, k++, If[FreeQ[Array[a, k - 1], a[k]], Print[k, " ", a[k]]; Sow[k]]]][[2, 1]]] (* Jean-François Alcover, Mar 03 2016, after Alois P. Heinz *)
Extensions
a(16)-a(39) from Alois P. Heinz, Feb 26 2016
Comments