A106242 Same triangle as A106243, but with rows read in boustrophedon manner, i.e., in the order in which they were created.
1, 0, 1, 0, 1, 1, 0, 2, 3, 3, 0, 6, 11, 13, 13, 0, 26, 50, 67, 73, 73, 0, 146, 286, 403, 479, 505, 505, 0, 1010, 1994, 2876, 3565, 3997, 4143, 4143, 0, 8286, 16426, 23988, 30429, 35299, 38303, 39313, 39313, 0, 78626, 156242, 229844, 295572, 349989, 390403, 415115, 423401, 423401
Offset: 0
Links
- Alois P. Heinz, Table of n, a(n) for n = 0..10010
Programs
-
Maple
T:= proc(n, k) option remember; local t; if n<1 or k<1 then 0 elif n=1 and k=1 then 1 elif n=1 and irem(k, 2)=1 or k=1 and irem(n, 2)=0 then 0 else t:= 1-2*irem(n+k, 2); T(n-t, k+t) + T(n, k-1)+T(n-1, k) fi end: seq (`if` (irem(d, 2)=1, seq (T(d-k, k), k=1..d-1), seq (T(n, d-n), n=1..d-1)), d=2..11); # Alois P. Heinz, Feb 08 2011 -
Mathematica
T[n_, k_] := T[n, k] = Module[{t}, Which[n<1 || k<1, 0, n == 1 && k == 1, 1, n == 1 && Mod[k, 2] == 1 || k == 1 && Mod[n, 2] == 0, 0, True, t = 1 - 2*Mod[n+k, 2]; T[n-t, k+t] + T[n, k-1] + T[n-1, k]]]; Table[If[Mod[d, 2] == 1, Table[T[d-k, k], {k, 1, d-1}], Table[T[n, d-n], {n, 1, d-1}]], {d, 2, 11}] // Flatten (* Jean-François Alcover, Jan 14 2014, translated from Alois P. Heinz's Maple code *)
Extensions
More terms from Alois P. Heinz, Feb 08 2011