A125732 Numbers n such that n=k*MiDi(n) for some integer k, where MiDi(n) = A103977(n) = "Minimal Difference of Divisors".
1, 2, 4, 8, 10, 16, 18, 32, 36, 44, 64, 72, 100, 128, 136, 144, 152, 162, 184, 196, 200, 256, 288, 324, 392, 400, 450, 512, 576, 648, 738, 748, 752, 784, 800, 882, 884, 900, 968, 1024, 1152, 1296, 1352, 1458, 1568, 1600, 1764, 1800, 1936, 2048, 2144, 2178, 2272
Offset: 1
Keywords
Links
- Amiram Eldar, Table of n, a(n) for n = 1..500
Programs
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Mathematica
midi[n_] := Module[{d = Divisors[n], c, p, m}, c = CoefficientList[Product[1 + x^i, {i, d}], x]; p = -1 + Position[c, ?(# > 0 &)] // Flatten; m = Length[p]; If[OddQ[m], If[(d = p[[(m + 1)/2]] - p[[(m - 1)/2]]) == 1, 0, d], p[[m/2 + 1]] - p[[m/2]]]]; s = {}; Do[m = midi[n]; If[m > 0 && Divisible[n, m], AppendTo[s, n]], {n, 1, 2000}]; s (* _Amiram Eldar, Dec 11 2019 *)
Extensions
More terms from R. J. Mathar, Nov 27 2007
More terms from Amiram Eldar, Dec 11 2019
Comments