A114189 Riordan array (1/(1+xc(-2x)), xc(-2x)/(1+xc(-2x))), c(x) the g.f. of A000108.
1, -1, 1, 3, -4, 1, -13, 19, -7, 1, 67, -102, 44, -10, 1, -381, 593, -278, 78, -13, 1, 2307, -3640, 1795, -568, 121, -16, 1, -14589, 23231, -11849, 4051, -999, 173, -19, 1, 95235, -152650, 79750, -28770, 7820, -1598, 234, -22, 1, -636925, 1025965, -545680, 204760, -59650, 13642, -2392, 304, -25, 1
Offset: 0
Examples
Triangle begins 1; -1, 1; 3, -4, 1; -13, 19, -7, 1; 67, -102, 44, -10, 1; -381, 593, -278, 78, -13, 1;
Programs
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Mathematica
c[x_] := (1 - Sqrt[1 - 4x])/(2x); (* The function RiordanArray is defined in A256893. *) RiordanArray[1/(1 + # c[-2#])&, # c[-2#]/(1 + # c[-2#])&, 10] // Flatten (* Jean-François Alcover, Jul 16 2019 *)
Formula
Riordan array ((3-sqrt(1+8x))/(2(1-x)), (sqrt(1+8x)-2x-1)/(2(1-x))).
T(n,k) = (-1)^(n-k)*A110506(n,k). - Philippe Deléham, Mar 24 2007
Comments