A157784 Triangle read by rows: the coefficient [x^k] of the polynomial Product_{i=1..n} (4^(i-1)-x), in row n and column 0 <= k <= n.
1, 1, -1, 4, -5, 1, 64, -84, 21, -1, 4096, -5440, 1428, -85, 1, 1048576, -1396736, 371008, -23188, 341, -1, 1073741824, -1431306240, 381308928, -24115520, 372372, -1365, 1, 4398046511104, -5863704100864, 1563272675328, -99158478848
Offset: 0
Examples
Triangle begins 1; 1, -1; 4, -5, 1; 64, -84, 21, -1; 4096, -5440, 1428, -85, 1; 1048576, -1396736, 371008, -23188, 341, -1; 1073741824, -1431306240, 381308928, -24115520, 372372, -1365, 1; 4398046511104, -5863704100864, 1563272675328, -99158478848, 1549351232, -5963412, 5461, -1; 72057594037927936, -96075326035066880, 25618523216674816, -1626175790120960, 25483729063936, -99253893440, 95436436, -21845, 1; Row n=3 represents 64 - 84*x + 21*x^2 - x^3.
Programs
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Maple
A157784 := proc(n,k) product( 4^(i-1)-x,i=1..n) ; coeftayl(%,x=0,k) ; end proc: # R. J. Mathar, Oct 15 2013
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Mathematica
Clear[f, q, M, n, m]; q = 4; f[k_, m_] := If[k == m, q^(n - k), If[m == 1 && k < n, q^(n - k), If[k == n && m == 1, -(n-1), If[k == n && m > 1, 1, 0]]]]; M[n_] := Table[f[k, m], {k, 1, n}, {m, 1, n}]; Table[M[n], {n, 1, 10}]; Join[{1}, Table[Expand[CharacteristicPolynomial[M[n], x]], {n, 1, 7}]]; a = Join[{{ 1}}, Table[CoefficientList[CharacteristicPolynomial[M[n], x], x], {n, 1, 7}]]; Flatten[a]
Comments