Number of (n+1) X (1+1) 0..1 arrays with every 2 X 2 subblock having a single 1 or two 1s on the same edge.

A251251

Number of (n+1) X (1+1) 0..1 arrays with every 2 X 2 subblock having a single 1 or two 1s on the same edge.

Terms

    a(0) =8a(1) =18a(2) =38a(3) =84a(4) =180a(5) =394a(6) =850a(7) =1852a(8) =4008a(9) =8714a(10) =18886a(11) =41020a(12) =88964a(13) =193138a(14) =419010a(15) =909460a(16) =1973352a(17) =4282722a(18) =9293318a(19) =20168132a(20) =43765364a(21) =94976442a(22) =206104402a(23) =447268364a(24) =970605128a(25) =2106305818a(26) =4570852838a(27) =9919165164a(28) =21525417860

External references