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A138857 Numbers such that all subsets of {a(1)^2,...,a(n)^2} have a different sum. 3
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; refs; listen; history; text; internal format)
OFFSET

1,2

COMMENTS

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.

LINKS

Table of n, a(n) for n=1..30.

FORMULA

A138857(n)=sqrt(A138858(n))

PROG

(PARI) {s=1; p=0; for( n=1, 23, until( !bitand( s, s>>(p^2) ), p++); s+=s<<(p^2); print1( p, ", "))}

CROSSREFS

Cf. A138858(n)=a(n)^2, A138856, A138000, A138001, A064934.

Sequence in context: A018591 A309591 A018669 * A018130 A160993 A171826

Adjacent sequences:  A138854 A138855 A138856 * A138858 A138859 A138860

KEYWORD

nonn

AUTHOR

M. F. Hasler, Apr 09 2008

EXTENSIONS

a(24)-a(30) from Donovan Johnson, Oct 03 2009

STATUS

approved

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Last modified January 19 14:53 EST 2020. Contains 331049 sequences. (Running on oeis4.)