Number of n X 2 0..2 arrays with rows and columns lexicographically nondecreasing and every element equal to at least one horizontal or vertical neighbor.

A201533

Number of n X 2 0..2 arrays with rows and columns lexicographically nondecreasing and every element equal to at least one horizontal or vertical neighbor.

Terms

    a(0) =3a(1) =9a(2) =25a(3) =69a(4) =175a(5) =410a(6) =899a(7) =1859a(8) =3649a(9) =6840a(10) =12311a(11) =21378a(12) =35964a(13) =58819a(14) =93800a(15) =146222a(16) =223292a(17) =334639a(18) =492954a(19) =714755a(20) =1021293a(21) =1439616a(22) =2003809a(23) =2756429a(24) =3750155a(25) =5049674a(26) =6733825a(27) =8898024a(28) =11656994a(29) =15147825

External references