

A110911


Positive integers that can be expressed in the form (a*2^a)/(b*2^b) where a and b are positive integers.


0



1, 3, 4, 5, 6, 8, 9, 10, 11, 12, 14, 16, 17, 18, 20, 24, 32, 33, 34, 36, 37, 40, 42, 48, 52, 64, 65, 66, 67, 68, 70, 72, 76, 80, 88, 96, 112, 128, 129, 130, 132, 135, 136, 142, 144, 156, 160, 184, 192, 240, 256, 257, 258, 260, 264, 272, 288, 320, 352, 384, 448, 512, 513
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OFFSET

1,2


COMMENTS

Odd values > 1 are of the form 2^n + odd divisor of n.


LINKS



EXAMPLE

6 is included because 6 = (6*2^6)/(4*2^4)
12 is a member because 12 = (3*2^3)/(1*2^1) = (9*2^9)/(6*2^6). Entries which are generated in two or more different ways are 1,12,20,32,48,72,80,112,160,192,256,576,768,..., .  Robert G. Wilson v, May 10 2006


MATHEMATICA

lst = {1}; Do[ If[ (Log[10, a] + a*Log[10, 2])  (Log[10, b] + b*Log[10, 2]) < 3 && IntegerQ[(a*2^a)/(b*2^b)], AppendTo[lst, (a*2^a)/(b*2^b)]; Print[(a*2^a)/(b*2^b)]], {a, 4620}, {b, Max[1, a  9(* =Log[2, 10^3] *)], a1}]; lst (* Robert G. Wilson v, May 10 2006 *)


CROSSREFS



KEYWORD

nonn


AUTHOR

Sam Handler (sam_5_5_5_0(AT)yahoo.com), Oct 09 2005


EXTENSIONS



STATUS

approved



