Number of n X 4 0,1 arrays indicating 2 X 2 subblocks of some larger (n+1) X 5 binary array having a sum of two or less, with rows and columns of the latter in lexicographically nondecreasing order.
A227261
Number of n X 4 0,1 arrays indicating 2 X 2 subblocks of some larger (n+1) X 5 binary array having a sum of two or less, with rows and columns of the latter in lexicographically nondecreasing order.
Terms
- a(0) =5a(1) =50a(2) =353a(3) =2201a(4) =11932a(5) =57146a(6) =244818a(7) =951917a(8) =3403038a(9) =11297855a(10) =35123154a(11) =102968348a(12) =286360987a(13) =759331583a(14) =1928166887a(15) =4706232142a(16) =11076831313a(17) =25210805133a(18) =55622829033a(19) =119222502647a(20) =248739253915a(21) =506020952898
External references
- oeis: A227261