Number of n X 2 nonnegative integer arrays with upper left 0 and lower right n+2-6 and value increasing by 0 or 1 with every step right or down.

A252924

Number of n X 2 nonnegative integer arrays with upper left 0 and lower right n+2-6 and value increasing by 0 or 1 with every step right or down.

Terms

    a(0) =0a(1) =0a(2) =0a(3) =1a(4) =19a(5) =120a(6) =483a(7) =1500a(8) =3923a(9) =9069a(10) =19095a(11) =37356a(12) =68860a(13) =120835a(14) =203424a(15) =330525a(16) =520794a(17) =798830a(18) =1196562a(19) =1754859a(20) =2525385a(21) =3572722a(22) =4976785a(23) =6835554a(24) =9268149a(25) =12418275a(26) =16458065a(27) =21592350a(28) =28063386a(29) =36156069

External references