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A129684 Exponential Riordan array [1/(1-x^2/2), x]. 2
1, 0, 1, 1, 0, 1, 0, 3, 0, 1, 6, 0, 6, 0, 1, 0, 30, 0, 10, 0, 1, 90, 0, 90, 0, 15, 0, 1, 0, 630, 0, 210, 0, 21, 0, 1, 2520, 0, 2520, 0, 420, 0, 28, 0, 1, 0, 22680, 0, 7560, 0, 756, 0, 36, 0, 1, 113400, 0, 113400, 0, 18900, 0, 1260, 0, 45, 0, 1 (list; table; graph; refs; listen; history; text; internal format)
OFFSET
0,8
COMMENTS
Row sums are A087214. Inverse is A129685.
LINKS
FORMULA
Number triangle T(n,k) = [k<=n](n!/k!)*(1/2^((n-k)/2))*(1+(-1)^(n-k))/2.
EXAMPLE
Triangle begins
1,
0, 1,
1, 0, 1,
0, 3, 0, 1,
6, 0, 6, 0, 1,
0, 30, 0, 10, 0, 1,
90, 0, 90, 0, 15, 0, 1,
0, 630, 0, 210, 0, 21, 0, 1
MATHEMATICA
(* The function RiordanArray is defined in A256893. *)
RiordanArray[1/(1 - #^2/2)&, #&, 11, True] // Flatten (* Jean-François Alcover, Jul 19 2019 *)
CROSSREFS
Sequence in context: A355172 A102765 A355257 * A247255 A105147 A335262
KEYWORD
easy,nonn,tabl
AUTHOR
Paul Barry, Apr 28 2007
STATUS
approved

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Last modified March 28 12:26 EDT 2024. Contains 371254 sequences. (Running on oeis4.)