Triangle read by rows: T(n,m) is the number of inequivalent n X m matrices under action of the Klein group, with one-fourth each of 1s, 2s, 3s and 4s (ordered occurrences rounded up/down if n*m != 0 mod 4).
A287020
Triangle read by rows: T(n,m) is the number of inequivalent n X m matrices under action of the Klein group, with one-fourth each of 1s, 2s, 3s and 4s (ordered occurrences rounded up/down if n*m != 0 mod 4).
Terms
- a(0) =1a(1) =1a(2) =1a(3) =1a(4) =1a(5) =6a(6) =1a(7) =1a(8) =46a(9) =1926a(10) =1a(11) =12a(12) =648a(13) =92544a(14) =15767640a(15) =1a(16) =30a(17) =6312a(18) =3943710a(19) =2933201376a(21) =1a(22) =90a(23) =92400a(24) =192994200a(25) =577186150464a(28) =1a(29) =318a(30) =1051140a(31) =10266445476
External references
- oeis: A287020