Number of nX4 0,1 arrays indicating 2X2 subblocks of some larger (n+1)X5 binary array having a sum of zero, with rows and columns of the latter in lexicographically nondecreasing order.
A227123
Number of nX4 0,1 arrays indicating 2X2 subblocks of some larger (n+1)X5 binary array having a sum of zero, with rows and columns of the latter in lexicographically nondecreasing order.
Terms
- a(0) =5a(1) =23a(2) =81a(3) =295a(4) =1079a(5) =3836a(6) =12954a(7) =41334a(8) =124956a(9) =359214a(10) =985377a(11) =2587934a(12) =6528298a(13) =15865511a(14) =37249628a(15) =84702904a(16) =186968944a(17) =401441143a(18) =839947739a(19) =1715449948a(20) =3424892827a(21) =6693385156a(22) =12820586861a(23) =24094606746a(24) =44476144089a(25) =80712174607
External references
- oeis: A227123