Number of alternating sign n X n matrices invariant under a half-turn.
A005158
Number of alternating sign n X n matrices invariant under a half-turn.
Terms
- a(0) =1a(1) =2a(2) =3a(3) =10a(4) =25a(5) =140a(6) =588a(7) =5544a(8) =39204a(9) =622908a(10) =7422987a(11) =198846076
External references
- oeis: A005158