A329773 a(n) is the least k such that A330241(k) = n.

0, 1, 5, 10, 11, 52, 53, 188, 189, 190, 191, 1318, 1319, 2516, 2517, 2518, 2519, 40990, 40991, 46852, 46853, 109198, 109199, 2885396, 2885397, 2885398, 2885399, 11744338, 11744339

Offset

0,3

Comments

This is an increasing sequence, since A330241(k+1) <= A330241(k)+1.

Links

Table of n, a(n) for n=0..28.

Example

a(4) = 11 because A330241(11) = 4 but none of A330241(0) to A330241(10) is 4.

Maple

F:= proc(n, L)
  local Ln, k, S, v;
  Ln[1]:= numtheory:-divisors(n);
  v:= 1;
  for k from 2 to nops(L)+1 do
    S:= select(`>`, L[k-1], v);
    if S = {} then return convert(Ln, list) fi;
    v:= min(S);
    Ln[k]:= S;
  od;
  convert(Ln, list);
end proc:
p:= 2: vmax:= 1: Res:= 0, 1:
for iter from 1 while vmax < 100 do
  q:= nextprime(p);
  if q-p > vmax then
    R:= [{1, p}];
    for n from p+1 to q do
      R:= F(n, R);
      v:= nops(R)-1;
      if v > vmax then
        vmax:= v;
        Res:= Res, n;
  fi od fi;
  p:= q;
od:
Res; # Robert Israel, Dec 08 2019

Crossrefs

Cf. A330241.

Sequence in context: A033649 A271922 A271920 * A213520 A241145 A050680

Adjacent sequences: A329770 A329771 A329772 * A329774 A329775 A329776

Keyword

nonn,more

Author

J. M. Bergot and Robert Israel, Dec 06 2019

Extensions

More terms from Robert Israel, Dec 08 2019

Status

approved