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Search: id:A143703
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| 3, 7, 15, 15, 21, 15, 39, 91, 555, 285, 915, 3333, 1155, 1267, 2769, 4935, 10005, 70635, 7035, 240045, 77745, 167055, 897429, 1231635, 1066065, 1174695
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OFFSET
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1,1
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COMMENT
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Product of distinct prime divisors of (2^n)*a(n)*(2^n-a(n)) is called also radical: rad((2^n)*a(n)*(2^n-a(n))
For numbers a(n) see A143700
For numbers 2^n-a(n) see A143701
For minimal values of rad((2^n)*a(n)*(2^n-a(n)) see A143702
For minimal values of rad(a(n)*(2^n-a(n)) see A143703 [? wrong A-number - N. J. A. Sloane (njas(AT)research.att.com), Nov 13 2008]
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MATHEMATICA
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a = {{1, 1}}; aa = {1}; bb = {1}; rr = {}; 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, r]; AppendTo[a, {x, logmax}], {x, 2, 15}]; rr/2 (*Artur Jasinski with assistance of Maximilian Hasler*)
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CROSSREFS
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A007947, A085152, A085153, A147298-A147307, A147638-A147643.
Sequence in context: A152677 A135374 A117589 this_sequence A098582 A089432 A111294
Adjacent sequences: A143700 A143701 A143702 this_sequence A143704 A143705 A143706
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KEYWORD
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nonn
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AUTHOR
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Artur Jasinski (grafix(AT)csl.pl), Nov 10 2008
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