A159040 A triangle of polynomial coefficients: p(x,n)=Sum[x^i*If[i == Floor[n/2] && Mod[n, 2] == 0, 0, If[i <= (less than or equal to) Floor[n/2], (-1)^i*A109128[n, i], -(-1)^(n - i)* A109128[n, i]]], {i, 0, n}]/(1 - x).
1, 1, 1, 1, -4, 1, 1, -6, -6, 1, 1, -8, 11, -8, 1, 1, -10, 19, 19, -10, 1, 1, -12, 29, -40, 29, -12, 1, 1, -14, 41, -70, -70, 41, -14, 1, 1, -16, 55, -112, 139, -112, 55, -16, 1, 1, -18, 71, -168, 251, 251, -168, 71, -18, 1, 1, -20, 89, -240, 419, -504, 419, -240, 89, -20, 1
Offset: 0
Examples
{1}, {1, 1}, {1, -4, 1}, {1, -6, -6, 1}, {1, -8, 11, -8, 1}, {1, -10, 19, 19, -10, 1}, {1, -12, 29, -40, 29, -12, 1}, {1, -14, 41, -70, -70, 41, -14, 1}, {1, -16, 55, -112, 139, -112, 55, -16, 1}, {1, -18, 71, -168, 251, 251, -168, 71, -18, 1}, {1, -20, 89, -240, 419, -504, 419, -240, 89, -20, 1}
Crossrefs
Programs
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Mathematica
Clear[A, p, n, i]; A[n_, 0] := 1; A[n_, n_] := 1; A[n_, k_] := A[n - 1, k - 1] + A[n - 1, k] + 1; p[x_, n_] = Sum[x^i*If[i == Floor[n/2] && Mod[n, 2] == 0, 0, If[i <= Floor[n/2], (-1)^i*A[n, i], -(-1)^(n - i)*A[n, i]]], {i, 0, n}]/(1 - x); Table[CoefficientList[FullSimplify[p[x, n]], x], {n, 1, 11}]; Flatten[%]
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