Number of alternating sign 2n+1 X 2n+1 matrices symmetric about the vertical axis (VSASM's); also 2n X 2n off-diagonally symmetric alternating sign matrices (OSASM's).
A005156
Number of alternating sign 2n+1 X 2n+1 matrices symmetric about the vertical axis (VSASM's); also 2n X 2n off-diagonally symmetric alternating sign matrices (OSASM's).
Terms
- a(0) =1a(1) =1a(2) =3a(3) =26a(4) =646a(5) =45885a(6) =9304650a(7) =5382618660
External references
- oeis: A005156