OFFSET
0,4
COMMENTS
FORMULA
G.f.: 1/(1-xy+x-x^2/(1-xy-2x^2/(1-xy-x-3x^2/(1-xy-2x-4x^2/(1-... (continued fraction).
EXAMPLE
Triangle begins
1,
-1, 1,
2, -2, 1,
-3, 6, -3, 1,
7, -12, 12, -4, 1,
-10, 35, -30, 20, -5, 1,
31, -60, 105, -60, 30, -6, 1,
-21, 217, -210, 245, -105, 42, -7, 1,
204, -168, 868, -560, 490, -168, 56, -8, 1
Production array is
-1, 1,
1, -1, 1,
1, 2, -1, 1,
1, 3, 3, -1, 1,
1, 4, 6, 4, -1, 1,
1, 5, 10, 10, 5, -1, 1,
1, 6, 15, 20, 15, 6, -1, 1,
1, 7, 21, 35, 35, 21, 7, -1, 1,
1, 8, 28, 56, 70, 56, 28, 8, -1, 1
MATHEMATICA
(* The function RiordanArray is defined in A256893. *)
RiordanArray[Exp[Exp[#] - 1 - 2 #]&, #&, 11, True] // Flatten (* Jean-François Alcover, Jul 19 2019 *)
CROSSREFS
KEYWORD
AUTHOR
Paul Barry, Apr 23 2009
STATUS
approved