Number of (n+1) X (2+1) 0..2 arrays with every 2 X 2 subblock summing to 4 and no 2 X 2 subblock having exactly two nonzero entries.

A251143

Number of (n+1) X (2+1) 0..2 arrays with every 2 X 2 subblock summing to 4 and no 2 X 2 subblock having exactly two nonzero entries.

Terms

    a(0) =27a(1) =49a(2) =87a(3) =161a(4) =299a(5) =565a(6) =1075a(7) =2065a(8) =3991a(9) =7761a(10) =15163a(11) =29749a(12) =58563a(13) =115617a(14) =228791a(15) =453633a(16) =900875a(17) =1791413a(18) =3566099a(19) =7105137a(20) =14166487a(21) =28262129a(22) =56409627a(23) =112633781a(24) =224967459a(25) =449449345a(26) =898113015a(27) =1794954785a(28) =3587852651

External references