

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



