English

Several results on sequences which are similar to the positive integers

Number Theory 2009-04-20 v4

Abstract

Sequence of positive integers {xn}n1\{x_n\}_{n\geq1} is called similar to N\mathbb {N} respectively a given property AA if for every n1n\geq1 the numbers xnx_n and nn are in the same class of equivalence respectively A(xnn(propA).A\enskip(x_n\sim n (prop \enskip A). If x1=a(>1)1(propA)x_1=a(>1)\sim1 (prop\enskip A) and xn>xn1x_n>x_{n-1} with the condition that xnx_n is the nearest to xn1x_{n-1} number such that xnn(propA),x_n\sim n (prop \enskip A), then the sequence {xn}\{x_n\} is called minimal recursive with the first term a({xn(a)}).a\enskip(\{x_n^{(a)}\}). We study two cases: A=A1A=A_1 is the value of exponent of the highest power of 2 dividing an integer and A=A2A=A_2 is the parity of the number of ones in the binary expansion of an integer. In the first case we prove that, for sufficiently large n,xn(a)=xn(3);n, \enskip x_n^{(a)}=x_n^{(3)}; in the second case we prove that, for a>4a>4 and sufficiently large n,xn(a)=xn(4).n,\enskip x_n^{(a)}=x_n^{(4)}.

Keywords

Cite

@article{arxiv.0904.2101,
  title  = {Several results on sequences which are similar to the positive integers},
  author = {Vladimir Shevelev},
  journal= {arXiv preprint arXiv:0904.2101},
  year   = {2009}
}

Comments

14 pages. I did some changes in Introduction to facilitate reading of the paper