a(n) = T(2n-1,n) + T(2n,n+1) + ... + T(3n-3,2n-2) = sum over a period of n-th diagonal of array T given by A049828.

A049833

a(n) = T(2n-1,n) + T(2n,n+1) + ... + T(3n-3,2n-2) = sum over a period of n-th diagonal of array T given by A049828.

Terms

    a(0) =0a(1) =1a(2) =5a(3) =13a(4) =23a(5) =40a(6) =54a(7) =80a(8) =104a(9) =131a(10) =161a(11) =209a(12) =231a(13) =288a(14) =332a(15) =376a(16) =426a(17) =499a(18) =549a(19) =631a(20) =673a(21) =748a(22) =826a(23) =940a(24) =972a(25) =1073a(26) =1177a(27) =1261a(28) =1347a(29) =1490

External references