Number of nX3 nonnegative integer arrays with upper left 0 and lower right n+3-5 and value increasing by 0 or 1 with every step right or down.
A252971
Number of nX3 nonnegative integer arrays with upper left 0 and lower right n+3-5 and value increasing by 0 or 1 with every step right or down.
Terms
- a(0) =0a(1) =1a(2) =18a(3) =153a(4) =770a(5) =2859a(6) =8694a(7) =22924a(8) =54272a(9) =118057a(10) =239798a(11) =460207a(12) =841930a(13) =1478451a(14) =2505634a(15) =4116442a(16) =6579440a(17) =10261761a(18) =15657290a(19) =23420901a(20) =34409666a(21) =49732043a(22) =70806142a(23) =99428264a(24) =137853008a(25) =188886345a(26) =255993166a(27) =343420923
External references
- oeis: A252971