This is a front-end for the Online Encyclopedia of Integer Sequences, made by Christian Perfect. The idea is to provide OEIS entries in non-ancient HTML, and then to think about how they're presented visually. The source code is on GitHub.
%I A342728 #23 Jan 14 2023 16:52:14
%S A342728 0,1,2,3,4,5,6,7,23,39,55,71,87,103,359,615,871,1127,1383,1639,5735,
%T A342728 9831,13927,18023,22119,26215,91751,157287,222823,288359,353895,
%U A342728 419431,1468007,2516583,3565159,4613735,5662311,6710887,23488103,40265319,57042535,73819751
%N A342728 a(n) is the least number k such that A066323(k) = n.
%C A342728 a(n) is the least number k whose sum of digits in base i-1 (or in base -4) is n.
%H A342728 Amiram Eldar, <a href="/A342728/b342728.txt">Table of n, a(n) for n = 0..1000</a>
%H A342728 Walter Penney, <a href="http://dx.doi.org/10.1145/321264.321274">A "binary" system for complex numbers</a>, Journal of the ACM, Vol. 12, No. 2 (1965), pp. 247-248.
%H A342728 <a href="/index/Rec#order_07">Index entries for linear recurrences with constant coefficients</a>, signature (1,0,0,0,0,16,-16).
%F A342728 a(n) = n for n <= 7, and a(n) = a(n-1) + 16*a(n-6) - 16*a(n-7) for n > 7.
%F A342728 G.f.: x*(1 + x + x^2 + x^3 + x^4 + x^5 - 15*x^6)/(1 - x - 16*x^6 + 16*x^7). - _Stefano Spezia_, Mar 20 2021
%F A342728 From _Greg Dresden_, Jun 21 2021: (Start)
%F A342728 a(3*n+1) = (24 + (4^n)*(25 - 9*(-1)^n))/40.
%F A342728 a(3*n+2) = (24 + (4^n)*(50 + 6*(-1)^n))/40.
%F A342728 a(3*n+3) = (24 + (4^n)*(75 + 21*(-1)^n))/40. (End)
%t A342728 Join[{0}, LinearRecurrence[{1,0,0,0,0,16,-16}, Range[7], 50]]
%Y A342728 Cf. A007608, A066321, A066323, A271472, A342725, A342726, A342727, A342729.
%K A342728 nonn,base,easy
%O A342728 0,3
%A A342728 _Amiram Eldar_, Mar 19 2021