Number of n X 2 0,1 arrays indicating 2 X 2 subblocks of some larger (n+1) X 3 binary array having a sum of one or less, with rows and columns of the latter in lexicographically nondecreasing order.
A227161
Number of n X 2 0,1 arrays indicating 2 X 2 subblocks of some larger (n+1) X 3 binary array having a sum of one or less, with rows and columns of the latter in lexicographically nondecreasing order.
Terms
- a(0) =1a(1) =3a(2) =8a(3) =18a(4) =36a(5) =66a(6) =113a(7) =183a(8) =283a(9) =421a(10) =606a(11) =848a(12) =1158a(13) =1548a(14) =2031a(15) =2621a(16) =3333a(17) =4183a(18) =5188a(19) =6366a(20) =7736a(21) =9318a(22) =11133a(23) =13203a(24) =15551a(25) =18201a(26) =21178a(27) =24508a(28) =28218a(29) =32336
External references
- oeis: A227161