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On the regularity of the Hankel determinant sequence of the characteristic sequence of powers

Number Theory 2018-06-25 v1 Formal Languages and Automata Theory

Abstract

For any sequences u={u(n)}n0,v={v(n)}n0,\mathbf{u}=\{u(n)\}_{n\geq0}, \mathbf{v}=\{v(n)\}_{n\geq0}, we define uv:={u(n)v(n)}n0\mathbf{u}\mathbf{v}:=\{u(n)v(n)\}_{n\geq0} and u+v:={u(n)+v(n)}n0\mathbf{u}+\mathbf{v}:=\{u(n)+v(n)\}_{n\geq0}. Let fi(x) (0i<k)f_i(x)~(0\leq i< k) be sequence polynomials whose coefficients are integer sequences. We say an integer sequence u={u(n)}n0\mathbf{u}=\{u(n)\}_{n\geq0} is a polynomial generated sequence if {u(kn+i)}n0=fi(u), (0i<k).\{u(kn+i)\}_{n\geq0}=f_i(\mathbf{u}),~(0\leq i< k). %Here we define uv:={u(n)v(n)}n0\mathbf{u}\mathbf{v}:=\{u(n)v(n)\}_{n\geq0} and u+v:={u(n)+v(n)}n0\mathbf{u}+\mathbf{v}:=\{u(n)+v(n)\}_{n\geq0} for any two sequences u={u(n)}n0,v={v(n)}n0.\mathbf{u}=\{u(n)\}_{n\geq0}, \mathbf{v}=\{v(n)\}_{n\geq0}. In this paper, we study the polynomial generated sequences. Assume k2k\geq2 and fi(x)=aix+bi (0i<k)f_i(x)=\mathbf{a}_ix+\mathbf{b}_i~(0\leq i< k). If ai\mathbf{a}_i are kk-automatic and bi\mathbf{b}_i are kk-regular for 0i<k0\leq i< k, then we prove that the corresponding polynomial generated sequences are kk-regular. As a application, we prove that the Hankel determinant sequence {det(pi+j)i,j=0n1}n0\{\det(p_{i+j})_{i,j=0}^{n-1}\}_{n\geq0} is 22-regular, where {p(n)}n0=0110100010000\{p(n)\}_{n\geq0}=0110100010000\cdots is the characteristic sequence of powers 2. Moreover, we give a answer of Cigler's conjecture about the Hankel determinants.

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Cite

@article{arxiv.1806.08729,
  title  = {On the regularity of the Hankel determinant sequence of the characteristic sequence of powers},
  author = {Ying-Jun Guo},
  journal= {arXiv preprint arXiv:1806.08729},
  year   = {2018}
}

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10 pages