OFFSET
0,4
COMMENTS
FORMULA
Exponential Riordan array [1/(cos(sqrt(3)*x)-sin(sqrt(3)*x)/sqrt(3)), sin(sqrt(3)*x)/(sqrt(3)*cos(sqrt(3)*x)-sin(sqrt(3)*x))].
EXAMPLE
Triangle begins:
1,
1, 1,
5, 4, 1,
21, 33, 9, 1,
153, 264, 114, 16, 1,
1209, 2769, 1410, 290, 25, 1,
12285, 32076, 20259, 5040, 615, 36, 1,
140589, 432657, 314811, 94899, 14175, 1155, 49, 1,
1871217, 6475536, 5423076, 1886304, 337974, 33936, 1988, 64, 1
Production matrix begins:
1, 1,
4, 3, 1,
0, 16, 5, 1,
0, 0, 36, 7, 1,
0, 0, 0, 64, 9, 1,
0, 0, 0, 0, 100, 11, 1,
0, 0, 0, 0, 0, 144, 13, 1,
0, 0, 0, 0, 0, 0, 196, 15, 1,
0, 0, 0, 0, 0, 0, 0, 256, 17, 1
0, 0, 0, 0, 0, 0, 0, 0, 324, 19, 1
MATHEMATICA
(* The function RiordanArray is defined in A256893. *)
RiordanArray[1/(Cos[Sqrt[3]*#] - Sin[Sqrt[3]*#]/Sqrt[3])&, Sin[Sqrt[3]*#]/ (Sqrt[3]*Cos[Sqrt[3]*#] - Sin[Sqrt[3]*#])&, 11, True] // Flatten (* Jean-François Alcover, Jul 19 2019 *)
CROSSREFS
KEYWORD
AUTHOR
Paul Barry, Dec 05 2010
STATUS
approved