login

Year-end appeal: Please make a donation to the OEIS Foundation to support ongoing development and maintenance of the OEIS. We are now in our 61st year, we have over 378,000 sequences, and we’ve reached 11,000 citations (which often say “discovered thanks to the OEIS”).

A115580
Array read by rows: row n (>= 1) gives the Betti numbers for the n-th element of the affine Weyl group of type B2_tilde (in Goresky's standard ordering).
0
1, 1, 1, 1, 1, 1, 1, 1, 2, 1, 1, 2, 1, 1, 2, 1, 1, 2, 1, 1, 2, 1, 1, 2, 2, 1, 1, 3, 3, 1, 1, 2, 2, 1, 1, 2, 2, 1, 1, 3, 3, 1, 1, 3, 3, 1, 1, 3, 3, 1, 1, 2, 2, 1, 1, 2, 2, 2, 1, 1, 3, 4, 3, 1, 1, 3, 5, 4, 1, 1, 3, 4, 3, 1, 1, 2, 2, 2, 1, 1, 3, 4, 3, 1, 1, 3, 4, 3, 1, 1, 3, 4, 3, 1, 1, 3, 4, 3, 1
OFFSET
1,9
COMMENTS
There are infinitely many rows.
EXAMPLE
Array begins:
1
1 1
1 1
1 1
1 2 1
1 2 1
1 2 1
1 2 1
1 2 1
CROSSREFS
KEYWORD
nonn,tabf
AUTHOR
Roger L. Bagula, Mar 04 2006
STATUS
approved