Number of 2 X 2 singular integer matrices with elements from {0,...,n} up to row and column permutation.
A064276
Number of 2 X 2 singular integer matrices with elements from {0,...,n} up to row and column permutation.
Terms
- a(0) =1a(1) =5a(2) =13a(3) =25a(4) =42a(5) =62a(6) =90a(7) =118a(8) =155a(9) =195a(10) =243a(11) =287a(12) =352a(13) =404a(14) =472a(15) =548a(16) =629a(17) =697a(18) =797a(19) =873a(20) =986a(21) =1094a(22) =1202a(23) =1294a(24) =1443a(25) =1559a(26) =1687a(27) =1823a(28) =1984a(29) =2100
External references
- oeis: A064276