Number of n X 3 0,1 arrays indicating 2 X 2 subblocks of some larger (n+1) X 4 binary array having a sum of zero, with rows and columns of the latter in lexicographically nondecreasing order.

A227122

Number of n X 3 0,1 arrays indicating 2 X 2 subblocks of some larger (n+1) X 4 binary array having a sum of zero, with rows and columns of the latter in lexicographically nondecreasing order.

Terms

    a(0) =4a(1) =13a(2) =33a(3) =81a(4) =202a(5) =492a(6) =1143a(7) =2524a(8) =5315a(9) =10718a(10) =20776a(11) =38839a(12) =70225a(13) =123134a(14) =209884a(15) =348550a(16) =565100a(17) =896136a(18) =1392363a(19) =2122925a(20) =3180764a(21) =4689176a(22) =6809757a(23) =9751952a(24) =13784441a(25) =19248618a(26) =26574442a(27) =36298963a(28) =49087851a(29) =65760282

External references