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Search: id:A138857
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| A138857 |
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Numbers such that all subsets of {a(1)^2,...,a(n)^2} have a different sum. |
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+0
3
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| 1, 2, 3, 4, 6, 9, 12, 18, 25, 34, 49, 70, 99, 140, 198, 280, 396, 560, 792, 1120, 1584, 2241, 3169, 4482, 6339, 8965, 12678, 17930, 25357, 35860
(list; graph; listen)
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OFFSET
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1,2
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COMMENT
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Since the ratio of two successive members of A138858 tends
to 1:2, we have here lim a(n+1)/a(n) = sqrt(2). More precisely, one
has a(n) ~ 2^(n/2+const.).
See A138858 for more comments.
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FORMULA
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A138857(n)=sqrt(A138858(n))
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PROGRAM
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(PARI) {s=1; p=0; for( n=1, 23, until( !bitand( s, s>>(p^2) ), p++); s+=s<<(p^2); print1( p, ", "))}
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CROSSREFS
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Cf. A138858(n)=a(n)^2, A138856, A138000, A138001, A064934.
Sequence in context: A094995 A018591 A018669 this_sequence A018130 A160993 A000792
Adjacent sequences: A138854 A138855 A138856 this_sequence A138858 A138859 A138860
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KEYWORD
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nonn
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AUTHOR
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M. F. Hasler (www.univ-ag.fr/~mhasler), Apr 09 2008
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EXTENSIONS
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a(24)-a(30) from Donovan Johnson (donovan.johnson(AT)yahoo.com), Oct 03 2009
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