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A158610 A sequence from a vector Markov with the matrix:t=4;M={{0,t},{t,1/t}} and characteristic polynomial :x^2-x/t-t^2. +0
1
1, 16, 272, 4368, 74000, 1192208, 20136208, 325341456, 5480210704, 88767623440, 1491701563664, 24216213164304, 406091813462288, 6605442383524112, 110564946629869840, 1801558196812042512, 30106184534058721552 (list; graph; listen)
OFFSET

0,2

COMMENT

Quadratic equation associated with group [3,3,5]

which instead of t=phi uses Integer t.

Phi(t)=(1+Sqrt[1+4*t^4])/(2*t);

Phi_star(t)=(1-Sqrt[1+4*t^4])/(2*t);

t=1:Phi(1)=(1+Sqrt[5])/2;

t=2:Phi(2)=(1 + Sqrt[65])/4;

t=3:Phi(3)=(1+5*Sqrt[13))/6;

t=4;Phi(4)=(1+5*Sqrt[41])/8.

General rule is:

Phi(t)+Phi_star(t)=1/t.

Table[(x /. NSolve[CharacteristicPolynomial[{{0, t}, {t, 1/t}}, x] == 0, x][[2]])

+ (x /. NSolve[CharacteristicPolynomial[{{0, t}, {t, 1/t}}, x] == 0, x][[1]])

- 1/ t, {t, 1, 20}]->zero

REFERENCES

H. S. M. Coxeter, Regular Polytopes, 3rd ed., Dover, NY, 1973,page 221.

FORMULA

t=4;M={{0,t},{t,1/t}};

and characteristic polynomial :x^2-x/t-t^2;

v(0)={1,1);v(n)=M.v(n-1);

out_(n)=t^n*v(n)[[1]]

a(n)=a(n-1)+256*a(n-2), a(0)=1, a(1)=16 . G.f.: (1+15x)/(1-x-256*x^2). [From Philippe DELEHAM (kolotoko(AT)wanadoo.fr), Mar 26 2009]

a(n)=(1/2)*{[(1/2)-(5/2)*sqrt(41)]^n+[(1/2)+(5/2)*sqrt(41)]^n}+(31/410)*sqrt(41)*{[(1/2)+(5/2)*sqrt(41)]^n-[(1/2)-(5/2)*sqrt(41)]^n}, with n>=0 [From Paolo P. Lava (ppl(AT)spl.at), Mar 30 2009]

MATHEMATICA

Clear[M, v, t, n];

M = {{0, t}, {t, 1/t}};

v[0] = {1, 1};

v[n_] := v[n] = M.v[n - 1];

t = 4;

a = Table[t^n*v[n][[1]], {n, 0, 30}]

CROSSREFS

Sequence in context: A158574 A000487 A002303 this_sequence A004382 A038758 A027776

Adjacent sequences: A158607 A158608 A158609 this_sequence A158611 A158612 A158613

KEYWORD

nonn,uned

AUTHOR

Roger L. Bagula (rlbagulatftn(AT)yahoo.com), Mar 22 2009

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Last modified November 25 20:09 EST 2009. Contains 167514 sequences.


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