Number of n X 3 binary arrays with row sums nondecreasing and columns lexicographically nondecreasing.

A267240

Number of n X 3 binary arrays with row sums nondecreasing and columns lexicographically nondecreasing.

Terms

    a(0) =4a(1) =13a(2) =42a(3) =141a(4) =486a(5) =1685a(6) =5804a(7) =19769a(8) =66544a(9) =221581a(10) =730918a(11) =2391717a(12) =7772610a(13) =25110933a(14) =80713016a(15) =258280817a(16) =823269116a(17) =2615088973a(18) =8281113730a(19) =26150883901a(20) =82375282494a(21) =258893742933a(22) =811984918692

External references