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 A303872 Triangle read by rows: T(0,0) = 1; T(n,k) = -T(n-1,k) + 2 T(n-1,k-1) for k = 0,1,...,n; T(n,k)=0 for n or k < 0. 6
 1, -1, 2, 1, -4, 4, -1, 6, -12, 8, 1, -8, 24, -32, 16, -1, 10, -40, 80, -80, 32, 1, -12, 60, -160, 240, -192, 64, -1, 14, -84, 280, -560, 672, -448, 128, 1, -16, 112, -448, 1120, -1792, 1792, -1024, 256, -1, 18, -144, 672, -2016, 4032, -5376, 4608, -2304, 512 (list; table; graph; refs; listen; history; text; internal format)
 OFFSET 0,3 COMMENTS Row n gives coefficients in expansion of (-1+2x)^n. Row sums=1. In the center-justified triangle, the numbers in skew diagonals pointing top-Left give the triangle in A133156 (coefficients of Chebyshev polynomials of the second kind), and the numbers in skew diagonals pointing top-right give the triangle in A305098. The coefficients in the expansion of 1/(1-x) are given by the sequence generated by the row sums. The generating function of the central terms is 1/sqrt(1+8x), signed version of A059304. REFERENCES Shara Lalo and Zagros Lalo, Polynomial Expansion Theorems and Number Triangles, Zana Publishing, 2018, ISBN: 978-1-9995914-0-3, pp. 389-391. LINKS Shara Lalo, Skew diagonals in center-justified triangle Paweł Lorek, Piotr Markowski, Absorption time and absorption probabilities for a family of multidimensional gambler models, arXiv:1812.00690 [math.PR], 2018. FORMULA Also has the g.f.: 1 / (1 + t - 2t*x). EXAMPLE Triangle begins: 1; -1, 2; 1, -4, 4; -1, 6, -12, 8; 1, -8, 24, -32, 16; -1, 10, -40, 80, -80, 32; 1, -12, 60, -160, 240, -192, 64; -1, 14, -84, 280, -560, 672, -448, 128; 1, -16, 112, -448, 1120, -1792, 1792, -1024, 256; MATHEMATICA T[0, 0] = 1; T[n_, k_] := If[n < 0 || k < 0, 0, - T[n - 1, k] + 2 T[n - 1, k - 1]]; Table[T[n, k], {n, 0, 9}, {k, 0, n}] // Flatten. For[i = 0, i < 4, i++, Print[CoefficientList[Expand[(-1 +2 x)^i], x]]]. PROG (PARI) T(n, k) = if ((n<0) || (k<0), 0, if ((n==0) && (k==0), 1, -T(n-1, k) + 2*T(n-1, k-1))); tabl(nn) = for (n=0, nn, for (k=0, n, print1(T(n, k), ", ")); print); \\ Michel Marcus, May 26 2018 CROSSREFS Row sums give A000012. Signed version of A013609 ((1+2*x)^n). Cf. A033999 (column 0). Sequence in context: A097750 A304623 A133544 * A013609 A154558 A220836 Adjacent sequences: A303869 A303870 A303871 * A303873 A303874 A303875 KEYWORD tabl,easy,sign AUTHOR Shara Lalo, May 25 2018 STATUS approved

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Last modified December 8 07:08 EST 2022. Contains 358673 sequences. (Running on oeis4.)