Irregular triangle read by rows: T(n, k) is the number of 2n-step closed walks on the square lattice having algebraic area k; n >= 0, 0 <= k <= floor(n^2/4).

A352838

Irregular triangle read by rows: T(n, k) is the number of 2n-step closed walks on the square lattice having algebraic area k; n >= 0, 0 <= k <= floor(n^2/4).

Terms

    a(0) =1a(1) =4a(2) =28a(3) =4a(4) =232a(5) =72a(6) =12a(7) =2156a(8) =1008a(9) =308a(10) =48a(11) =8a(12) =21944a(13) =13160a(14) =5540a(15) =1560a(16) =420a(17) =80a(18) =20a(19) =240280a(20) =168780a(21) =87192a(22) =33628a(23) =11964a(24) =3636a(25) =1200a(26) =264a(27) =72a(28) =12a(29) =2787320

External references