login

Year-end appeal: Please make a donation to the OEIS Foundation to support ongoing development and maintenance of the OEIS. We are now in our 61st year, we have over 378,000 sequences, and we’ve reached 11,000 citations (which often say “discovered thanks to the OEIS”).

A138064
A triangular sequence from the Z/nZ matrix addition tables as in sequence A095897 as coefficients of characteristic polynomials: M(n,m)=Mod[n + m, d] for n <=m<=d.
0
1, 0, -1, -1, 0, 1, -9, 3, 3, -1, 96, 32, -20, -4, 1, 1250, -125, -250, 25, 10, -1, -19440, -5184, 2592, 576, -93, -12, 1, -352947, 16807, 50421, -2401, -2058, 98, 21, -1, 7340032, 1572864, -753664, -147456, 24064, 3840, -272, -24, 1, 172186884, -4782969, -19131876, 531441, 708588, -19683, -9720, 270, 36
OFFSET
1,7
COMMENTS
Row sums are:
{1, -1, 0, -4, 105, 909, -21560, -290060, 8039385, 149482970, -4868582664};
These are Gary W. Adamson's matrices: I plugged them into my existing matrix program.
FORMULA
M(n,m)=Mod[n + m, d] for n <=m<=d; p(x,n)=CharacteristicPolynomial(M(n,m)); out_n,m=Coefficients(p(x,n));
EXAMPLE
{1},
{0, -1},
{-1,0, 1},
{-9, 3, 3, -1},
{96, 32, -20, -4, 1},
{1250, -125, -250, 25, 10, -1},
{-19440, -5184, 2592, 576, -93, -12, 1},
{-352947, 16807, 50421, -2401, -2058, 98, 21, -1},
{7340032, 1572864, -753664, -147456, 24064, 3840, -272, -24, 1},
{172186884, -4782969, -19131876, 531441, 708588, -19683, -9720, 270, 36, -1},
{-4500000000, -800000000, 380000000, 64000000, -11050000, -1680000, 132000, 16000, -625, -40, 1}
MATHEMATICA
M[d_] := Table[Mod[n + m, d], {n, 0, d - 1}, {m, 0, d - 1}]; a1 = Table[M[d], {d, 1, 10}]; Table[Det[M[d]], {d, 1, 10}]; g = Table[Det[M[d] - x*IdentityMatrix[d]], {d, 1, 10}]; a = Join[{{1}}, Table[CoefficientList[Det[M[d] - x*IdentityMatrix[d]], x], {d, 1, 10}]]; Flatten[a] MatrixForm[a];
CROSSREFS
Cf. A095897.
Sequence in context: A363848 A011112 A374752 * A063569 A037921 A327135
KEYWORD
uned,tabl,sign
AUTHOR
STATUS
approved