A125733 - OEIS

%I #8 Dec 11 2019 05:05:24

%S 1,2,4,8,5,16,18,32,36,11,64,72,100,128,68,144,38,162,23,196,200,256,

%T 288,324,392,400,450,512,576,648,369,374,47,784,800,882,221,900,968,

%U 1024,1152,1296,1352,1458,1568,1600,1764,1800,1936,2048,536,2178,284,2304

%N a(n) gives k numbers from A125732.

%H Amiram Eldar, <a href="/A125733/b125733.txt">Table of n, a(n) for n = 1..500</a>

%F a(n) = A125732(n)/A103977(A125732(n)). - _Amiram Eldar_, Dec 11 2019

%t 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/m]], {n, 1, 2000}]; s (* _Amiram Eldar_, Dec 11 2019 *)

%Y Cf. A103977, A125732.

%K nonn

%O 1,2

%A _Yasutoshi Kohmoto_, Jan 01 2007

%E a(7) corrected and more terms added by _Amiram Eldar_, Dec 11 2019