Number of n X 2 nonnegative integer arrays with upper left 0 and lower right n+2-4 and value increasing by 0 or 1 with every step right or down.

A252870

Number of n X 2 nonnegative integer arrays with upper left 0 and lower right n+2-4 and value increasing by 0 or 1 with every step right or down.

Terms

    a(0) =0a(1) =1a(2) =8a(3) =26a(4) =61a(5) =120a(6) =211a(7) =343a(8) =526a(9) =771a(10) =1090a(11) =1496a(12) =2003a(13) =2626a(14) =3381a(15) =4285a(16) =5356a(17) =6613a(18) =8076a(19) =9766a(20) =11705a(21) =13916a(22) =16423a(23) =19251a(24) =22426a(25) =25975a(26) =29926a(27) =34308a(28) =39151a(29) =44486

External references