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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 0
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 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,2

COMMENTS

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

LINKS

Table of n, a(n) for n=1..25.

CROSSREFS

Cf. A172020.

Sequence in context: A116931 A206558 A145810 * A205478 A262966 A034397

Adjacent sequences:  A172145 A172146 A172147 * A172149 A172150 A172151

KEYWORD

nonn

AUTHOR

John W. Layman, Jan 26 2010

STATUS

approved

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Last modified October 21 02:41 EDT 2018. Contains 316405 sequences. (Running on oeis4.)