A127410
Negative value of coefficient of x^(n-5) in the characteristic polynomial of a certain n X n integer circulant matrix.
Original entry on oeis.org
1875, 25920, 184877, 917504, 3582306, 11760000, 33820710, 87588864, 208295373, 461452992, 962836875, 1908408320, 3617795636, 6595852032, 11617856508, 19845120000, 32979115575, 53463778368, 84747328281, 131616866304, 200621093750, 300598812800, 443333396610
Offset: 5
The circulant matrix for n = 5 is
[1 2 3 4 5]
[5 1 2 3 4]
[4 5 1 2 3]
[3 4 5 1 2]
[2 3 4 5 1]
The characteristic polynomial of this matrix is x^5 - 5*x^4 -100*x^3 - 625*x^2 - 1750*x - 1875. The coefficient of x^(n-5) is -1875, hence a(5) = 1875.
- Daniel Zwillinger, ed., "CRC Standard Mathematical Tables and Formulae", 31st Edition, ISBN 1-58488-291, Section 2.6.2.25 (page 141) and Section 2.6.11.3 (page 152).
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[ -Coefficient(CharacteristicPolynomial(Matrix(IntegerRing(), n, n, [< i, j, 1 + (j-i) mod n > : i, j in [1..n] ] )), n-5) : n in [5..24] ]; // Klaus Brockhaus, Jan 27 2007
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[ (n-4)*(n-3)*(n-2)*(n-1)*n^5*(4*n+16) / (2*Factorial(6)) : n in [5..24] ]; // Klaus Brockhaus, Jan 27 2007
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n * (n+1) * (n+2) * (n+3) * (n+4)^5 * (4*n + 32) / (2 * factorial(6)); % Paul Max Payton, Jan 14 2007
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a(n) = {-polcoef(charpoly(matrix(n,n,i,j,(j-i)%n+1),x),n-5)} \\ Klaus Brockhaus, Jan 27 2007
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a(n) = {(4*n^10-24*n^9-20*n^8+360*n^7-704*n^6+384*n^5)/(2*6!)} \\ Klaus Brockhaus, Jan 27 2007
A127411
Negative value of coefficient of x^(n-6) in the characteristic polynomial of a certain n X n integer circulant matrix.
Original entry on oeis.org
27216, 453789, 3866624, 22674816, 103500000, 393286542, 1297410048, 3822832728, 10267329072, 25518796875, 59378761728, 130535973152, 273106821312, 547049504268, 1054272000000, 1962916959024, 3543150344976, 6218839661001, 10640820731904, 17789062500000
Offset: 6
The circulant matrix for n = 6 is
[1 2 3 4 5 6]
[6 1 2 3 4 5]
[5 6 1 2 3 4]
[4 5 6 1 2 3]
[3 4 5 6 1 2]
[2 3 4 5 6 1]
The characteristic polynomial of this matrix is x^6 - 6*x^5 -196*x^4 - 1980*x^3 - 10044*x^2 - 25920*x - 27216. The coefficient of x^(n-6) is -27216, hence a(6) = 27216.
- Daniel Zwillinger, ed., "CRC Standard Mathematical Tables and Formulae", 31st Edition, ISBN 1-58488-291, Section 2.6.2.25 (page 141) and Section 2.6.11.3 (page 152).
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[ -Coefficient(CharacteristicPolynomial(Matrix(IntegerRing(), n, n, [< i, j, 1 + (j-i) mod n > : i, j in [1..n] ] )), n-6) : n in [6..22] ]; // Klaus Brockhaus, Jan 27 2007
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[ (n-5)*(n-4)*(n-3)*(n-2)*(n-1)*n^6*(5*n+19) / (2*Factorial(7)) : n in [6..22] ]; // Klaus Brockhaus, Jan 27 2007
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n * (n+1) * (n+2) * (n+3) * (n+4) * (n+5)^6 * (5*n + 44) / (2*factorial(7)); % Paul Max Payton, Jan 14 2007
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a(n) = {-polcoef(charpoly(matrix(n,n,i,j,(j-i)%n+1),x),n-6)} \\ Klaus Brockhaus, Jan 27 2007
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a(n) = {(5*n^12-56*n^11+140*n^10+490*n^9-2905*n^8+4606*n^7-2280*n^6)/(2*7!)} \\ Klaus Brockhaus, Jan 27 2007
A127407
Negative value of coefficient of x^(n-2) in the characteristic polynomial of a certain n X n integer circulant matrix.
Original entry on oeis.org
3, 15, 44, 100, 195, 343, 560, 864, 1275, 1815, 2508, 3380, 4459, 5775, 7360, 9248, 11475, 14079, 17100, 20580, 24563, 29095, 34224, 40000, 46475, 53703, 61740, 70644, 80475, 91295, 103168, 116160, 130339, 145775, 162540, 180708, 200355
Offset: 2
The circulant matrix for n = 5 is
[1 2 3 4 5]
[5 1 2 3 4]
[4 5 1 2 3]
[3 4 5 1 2]
[2 3 4 5 1]
The characteristic polynomial of this matrix is x^5 - 5*x^4 -100*x^3 - 625*x^2 - 1750*x - 1875. The coefficient of x^(n-2) is -100, hence a(5) = 100.
- Daniel Zwillinger, ed., "CRC Standard Mathematical Tables and Formulae", 31st Edition, ISBN 1-58488-291, Section 2.6.2.25 (page 141) and Section 2.6.11.3 (page 152).
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[ -Coefficient(CharacteristicPolynomial(Matrix(IntegerRing(), n, n, [< i, j, 1 + (j-i) mod n > : i, j in [1..n] ] )), n-2) : n in [2..38] ]; // Klaus Brockhaus, Jan 27 2007
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[ (n-1) * n^2 * (n+7) / (2 * Factorial(3)) : n in [2..38] ]; // Klaus Brockhaus, Jan 27 2007
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n * (n+1)^2 * (n+8) / (2 * factorial(3)); % Paul Max Payton, Jan 14 2007
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a(n) = {-polcoeff(charpoly(matrix(n,n,i,j,(j-i)%n+1),x),n-2)} \\ Klaus Brockhaus, Jan 27 2007
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a(n) = {(n^4+6*n^3-7*n^2)/(2*3!)} \\ Klaus Brockhaus, Jan 27 2007
A127408
Negative value of coefficient of x^(n-3) in the characteristic polynomial of a certain n X n integer circulant matrix.
Original entry on oeis.org
18, 144, 625, 1980, 5145, 11648, 23814, 45000, 79860, 134640, 217503, 338884, 511875, 752640, 1080860, 1520208, 2098854, 2850000, 3812445, 5031180, 6558013, 8452224, 10781250, 13621400, 17058600, 21189168, 26120619, 31972500, 38877255
Offset: 3
The circulant matrix for n = 5 is
[1 2 3 4 5]
[5 1 2 3 4]
[4 5 1 2 3]
[3 4 5 1 2]
[2 3 4 5 1]
The characteristic polynomial of this matrix is x^5 - 5*x^4 -100*x^3 - 625*x^2 - 1750*x - 1875. The coefficient of x^(n-3) is -625, hence a(5) = 625.
- Daniel Zwillinger, Ed., "CRC Standard Mathematical Tables and Formulae", 31st Edition, ISBN 1-58488-291, Section 2.6.2.25 (page 141) and Section 2.6.11.3 (page 152).
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[ -Coefficient(CharacteristicPolynomial(Matrix(IntegerRing(), n, n, [< i, j, 1 + (j-i) mod n > : i, j in [1..n] ] )), n-3) : n in [3..31] ] ; // Klaus Brockhaus, Jan 26 2007
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[ (n-2) * (n-1) * n^3 * (2*(n-2) + 14) / (2 * Factorial(4)) : n in [3..31] ] ; // Klaus Brockhaus, Jan 26 2007
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n * (n+1) * (n+2)^3 * (2*n + 14) / (2 * factorial(4)); % Paul Max Payton, Jan 14 2007
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a(n) = {-polcoef(charpoly(matrix(n,n,i,j,(j-i)%n+1),x),n-3)} \\ Klaus Brockhaus, Jan 26 2007
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a(n) = {(n^6+2*n^5-13*n^4+10*n^3)/4!} \\ Klaus Brockhaus, Jan 26 2007
A127409
Negative value of coefficient of x^(n-4) in the characteristic polynomial of a certain n X n integer circulant matrix.
Original entry on oeis.org
160, 1750, 10044, 40817, 132608, 367416, 903000, 2020458, 4191264, 8168446, 15107092, 26719875, 45473792, 74834816, 119567664, 186098388, 282948000, 421245846, 615331948, 883458037, 1248597504, 1739375000, 2391126920
Offset: 4
The circulant matrix for n = 5 is
[1 2 3 4 5]
[5 1 2 3 4]
[4 5 1 2 3]
[3 4 5 1 2]
[2 3 4 5 1]
The characteristic polynomial of this matrix is x^5 - 5*x^4 -100*x^3 - 625*x^2 - 1750*x - 1875. The coefficient of x^(n-4) is -1750, hence a(5) = 1750.
- Daniel Zwillinger, ed., "CRC Standard Mathematical Tables and Formulae", 31st Edition, ISBN 1-58488-291, Section 2.6.2.25 (page 141) and Section 2.6.11.3 (page 152).
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[ -Coefficient(CharacteristicPolynomial(Matrix(IntegerRing(), n, n, [< i, j, 1 + (j-i) mod n > : i, j in [1..n] ] )), n-4) : n in [4..26] ]; // Klaus Brockhaus, Jan 27 2007
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[ (n-3)*(n-2)*(n-1)*n^4*(3*n+13) / (2 * Factorial(5)) : n in [4..26] ]; // Klaus Brockhaus, Jan 27 2007
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n * (n+1) * (n+2) * (n+3)^4 * (3*n + 22) / (2 * factorial(5)); % Paul Max Payton, Jan 14 2007
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a(n) = {-polcoeff(charpoly(matrix(n,n,i,j,(j-i)%n+1),x),n-4)} \\ Klaus Brockhaus, Jan 27 2007
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a(n) = {(3*n^8 - 5*n^7 - 45*n^6 + 125*n^5 - 78*n^4)/(2*5!)} \\ Klaus Brockhaus, Jan 27 2007
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