OFFSET
0,12
COMMENTS
Triangle read by rows, Pascal's triangle (A007318) rows repeated.
Riordan array (1/(1-x), x^2/(1-x^2)). - Philippe Deléham, Feb 27 2012
LINKS
Reinhard Zumkeller, Rows n = 0..150 of triangle, flattened
FORMULA
EXAMPLE
Triangle begins:
1;
1, 0;
1, 1, 0;
1, 1, 0, 0;
1, 2, 1, 0, 0;
1, 2, 1, 0, 0, 0;
1, 3, 3, 1, 0, 0, 0;
1, 3, 3, 1, 0, 0, 0, 0;
1, 4, 6, 4, 1, 0, 0, 0, 0; ...
MATHEMATICA
m = 13;
(* DELTA is defined in A084938 *)
DELTA[Join[{1, 0, -1}, Table[0, {m}]], Join[{0, 1, -1}, Table[0, {m}]], m] // Flatten (* Jean-François Alcover, Feb 19 2020 *)
T[n_, k_] := If[n<0, 0, Binomial[Floor[n/2], k]]; (* Michael Somos, Oct 01 2022 *)
PROG
(Haskell)
a152815 n k = a152815_tabl !! n !! k
a152815_row n = a152815_tabl !! n
a152815_tabl = [1] : [1, 0] : t [1, 0] where
t ys = zs : zs' : t zs' where
zs' = zs ++ [0]; zs = zipWith (+) ([0] ++ ys) (ys ++ [0])
-- Reinhard Zumkeller, Feb 28 2012
{T(n, k) = if(n<0, 0, binomial(n\2, k))}; /* Michael Somos, Oct 01 2022 */
CROSSREFS
KEYWORD
AUTHOR
Philippe Deléham, Dec 13 2008
EXTENSIONS
Example corrected by Philippe Deléham, Dec 13 2008
STATUS
approved