A138857 Numbers such that all subsets of {a(1)^2,...,a(n)^2} have a different sum.

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

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