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%I #21 Aug 12 2020 12:00:02
%S 2,6,14,30,30,42,30,78,182,1110,570,1830,6666,2310,2534,5538,9870,
%T 20010,141270,14070,480090,155490,334110,1794858,2463270,2132130,
%U 2349390
%N a(n) is the minimal values of A007947((2^n)*m*(2^n-m)).
%C The product of distinct prime divisors of (2^n)*m*(2^n-m) is also called the radical of that number: rad((2^n)*m*(2^n-m)).
%C For numbers m see A143700.
%t aa = {1}; bb = {1}; rr = {2}; Do[logmax = 0; k = 2^x; w = Floor[(k - 1)/2]; Do[m = FactorInteger[n (k - n)]; rad = 1; Do[rad = rad m[[s]][[1]], {s, 1, Length[m]}]; log = Log[k]/Log[rad]; If[log > logmax, bmin = k - n; amax = n; logmax = log; r = rad], {n, 1, w, 2}]; Print[{x, amax}]; AppendTo[aa, amax]; AppendTo[bb, bmin]; AppendTo[rr, 2*r]; AppendTo[a, {x, logmax}], {x, 2, 15}]; rr (* _Artur Jasinski_ with assistance of _M. F. Hasler_ *)
%Y Cf. A007947, A085152, A085153, A147298-A147307, A147638-A147643.
%K nonn,more
%O 1,1
%A _Artur Jasinski_, Nov 10 2008
%E Name changed and a(1) added by _Jinyuan Wang_, Aug 11 2020
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