Q. about {0,1}-matrices.

[Artur]

Dear Jonathan, Neil and Rest of Seqfans,
In giving these names we have to think yet about next sequence 0 or 1, 2,  
40, 584,
I don't have yet a(5).
My proposal for these sequence follow Jonatan will be (because these is  
gracile in comparision with these robust):
Call an n X n matrix gracile if the top left i X i submatrix is  
noninvertible for all i = 1..n.
ARTUR


Dnia 08-01-2007 o 18:34:21 Jonathan Post <jvospost3 at gmail.com> napisał(a):

> I suggest a better name for "binary matrices which are not robust":  
> gracile.
>
> A126603 versus A125507.
>
> Robust and Gracile are antonyms, used as relative terms in  
> paleoanthroplogy,
> generally of bone proportions (i.e., thickness relative to length).
> Frequently used for Australopithecus, as in "Australopithecus afarensis  
> and
> Australopithecus are known as gracile australopithecines, because of  
> their
> relatively lighter build, especially in the skull and teeth. Paranthropus
> aethiopicus, robustus, and boisei are robust australopithecines."