cp's OEIS Frontend

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.

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A358055 a(n) is the least m such that A358052(m,k) = n for some k.

Original entry on oeis.org

1, 2, 5, 8, 14, 20, 32, 38, 59, 59, 63, 116, 122, 158, 158, 218, 278, 278, 402, 548, 642, 642, 642, 642, 642, 1062, 1062, 1668, 2474, 2690, 2690, 2690, 2690, 2690, 3170, 3170, 3170, 3170, 3170, 3170, 3170, 9260, 9260, 9260, 9788, 9788, 11772, 11942, 11942, 11942, 11942, 11942
Offset: 1

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Author

J. M. Bergot and Robert Israel, Oct 27 2022

Keywords

Comments

a(n) is the least m such that iteration of the map x -> floor(m/x) + (m mod x), starting at some k in [1,m], produces n distinct values before repeating.

Examples

			a(4) = 8 because A358052(8,6) = 4 and this is the first appearance of 4 in A358052.
Thus the map x -> floor(8/x) + (8 mod x) starting at 6 produces 4 distinct values before repeating: 6 -> 3 -> 4 -> 2 -> 4.
		

Crossrefs

Programs

  • Maple
    f:= proc(n, k) local x, S, count;
      S:= {k};
      x:= k;
      for count from 1 do
         x:= iquo(n, x) + irem(n, x);
         if member(x, S) then return count fi;
         S:= S union {x};
      od
    end proc:
    V:= Vector(50): count:= 0:
    for n from 1 while count < 50 do
      for k from 1 to n do
        v:= f(n,k);
        if v <= 50 and V[v] = 0 then
           V[v]:= n; count:= count+1;
        fi
    od od:
    convert(V,list);
  • Mathematica
    f[n_, k_] := Module[{x, S, count}, S = {k}; x = k; For[count = 1, True, count++, x = Quotient[n, x] + Mod[n, x]; If[MemberQ[S, x], Return@count]; S = S~Union~{x}]];
    V = Table[0, {vmax = 40}]; count = 0;
    For[n = 1, count < vmax, n++, For[k = 1, k <= n, k++, v = f[n, k]; If[v <= vmax && V[[v]] == 0, Print[n]; V[[v]] = n; count++]]];
    V (* Jean-François Alcover, Mar 12 2024, after Maple code *)
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