OFFSET
1,3
COMMENTS
Related to the sequence a'(n): 1,1,2,3,7,21,131. The sequence a'(n) has a recursive definition.
The following holds: a(n)>a'(n) for n>6.
REFERENCES
Ilda P. F. da Silva, Recursivity and geometry of the hypercube, Linear Algebra and its Apllications, 397(2005),223-233
EXAMPLE
For n=3 a(3)=2 because the 2 vectors (0,0,1,1) and (1,1,1,1) describe all the real planes spanned by the points of {-1,1}^3.
CROSSREFS
KEYWORD
hard,nonn
AUTHOR
Ilda P. F. da Silva (isilva(AT)cii.fc.ul.pt), Jan 26 2009
STATUS
approved