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.
N:= 100: # for a(1)..a(N)
V:= Vector(N): S:= {0,1}:
V[1]:= 1:
for n from 2 to N do
v:= floor(V[n-1]/2);
if member(v, S) then V[n]:= 2*n
else V[n]:= v
fi;
S:= S union {V[n]}
od:
convert(V,list); # Robert Israel, Feb 09 2020
f[s_List] := Block[{len = Length@s, m = Floor[s[[-1]]/2]}, Append[s, If[MemberQ[s, m], 2 len, m]]]; Rest@Nest[f, {0, 1}, 65] (* Robert G. Wilson v, Aug 09 2018 *)
S:= {0,1}: A[1]:= 1:
for n from 2 to 100 do
v:= floor(A[n-1]/2);
if not member(v,S) then A[n]:= v
else A[n]:= 5*n
fi;
S:= S union {A[n]};
od:
seq(A[i],i=1..100); # Robert Israel, Aug 07 2018
f[s_List] := Block[{len = Length@s, m = Floor[s[[-1]]/2]}, Append[s, If[MemberQ[s, m], 5 len, m]]]; Rest@ Nest[f, {0, 1}, 65] (* Robert G. Wilson v, Aug 07 2018 *)
a = {0, 1, 1}; Do[AppendTo[a, If[MemberQ[a, c = Quotient[a[[-1]], 3]], a[[-1]] + a[[-2]], c]], {n, 3, 59}]; Delete[a, 1] (* Ivan Neretin, Sep 04 2015 *)
R:= 2: S:= {2}: a:= 2:
for n from 2 to 100 do
t:= floor(a/2);
if t <> 0 and not member(t,S) then a:= t else a:= 2*n fi;
R:= R,a; S:= S union {a};
od:
R; # Robert Israel, Aug 03 2025
Delete[#, 3] &@ Nest[Append[#1, If[FreeQ[#1, #2], #2, 4 #3]] & @@ {#, Floor[#[[-1]]/2], Length@ #} &, {2}, 59] (* Michael De Vlieger, Oct 06 2019 *)
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