a(n) is the number of 2 X 2 matrices with elements 1..n where at least one row, at least one column and at least one of the two diagonals is strictly increasing.
A391092
a(n) is the number of 2 X 2 matrices with elements 1..n where at least one row, at least one column and at least one of the two diagonals is strictly increasing.
Terms
- a(0) =0a(1) =0a(2) =2a(3) =19a(4) =76a(5) =210a(6) =470a(7) =917a(8) =1624a(9) =2676a(10) =4170a(11) =6215a(12) =8932a(13) =12454a(14) =16926a(15) =22505a(16) =29360a(17) =37672a(18) =47634a(19) =59451a(20) =73340a(21) =89530a(22) =108262a(23) =129789a(24) =154376a(25) =182300a(26) =213850a(27) =249327a(28) =289044a(29) =333326
External references
- oeis: A391092