a(n) is the number of 2 X 2 matrices with elements 1..n where at least one row and at least one column is strictly increasing.
A390922
a(n) is the number of 2 X 2 matrices with elements 1..n where at least one row and at least one column is strictly increasing.
Terms
- a(0) =0a(1) =0a(2) =4a(3) =29a(4) =106a(5) =280a(6) =610a(7) =1169a(8) =2044a(9) =3336a(10) =5160a(11) =7645a(12) =10934a(13) =15184a(14) =20566a(15) =27265a(16) =35480a(17) =45424a(18) =57324a(19) =71421a(20) =87970a(21) =107240a(22) =129514a(23) =155089a(24) =184276a(25) =217400a(26) =254800a(27) =296829a(28) =343854a(29) =396256
External references
- oeis: A390922