

A172148


Number of subsets S of {1,2,3,...,n} with the property that if x is a member of S then at least one of x/2 and 2x is also a member of S


1



1, 2, 2, 4, 4, 8, 8, 14, 14, 28, 28, 56, 56, 112, 112, 192, 192, 384, 384, 768, 768, 1536, 1536, 2688, 2688, 5376, 5376, 10752, 10752, 21504, 21504, 37632, 37632, 75264, 75264, 150528, 150528, 301056, 301056, 526848, 526848, 1053696, 1053696, 2107392, 2107392
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OFFSET

1,2


COMMENTS

For the terms a(1) through a(25) is it seen that if n is odd then a(n)=a(n1); also that if n is not a multiple of 4 then a(2n)=2a(2n2). Does this behavior continue?


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CROSSREFS



KEYWORD

nonn


AUTHOR



EXTENSIONS



STATUS

approved



