RosettaCodeData/Task/Hailstone-sequence/SETL/hailstone-sequence.setl

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program hailstone_sequence;
hail27 := hailstone(27);
print("The hailstone sequence for the number 27 has", #hail27, "elements,");
print("starting with", hail27(..4), "and ending with", hail27(#hail27-3..));
sizes := [#hailstone(n) : n in [1..99999]];
maxsize := max/sizes;
maxelem := [n : n in [1..#sizes] | sizes(n) = maxsize](1);
print("The number < 100,000 with the longest hailstone sequence is",maxelem);
print("The length of its sequence is",sizes(maxelem));
proc hailstone(n);
seq := [];
loop doing seq with:= n; while n/=1 do
if even n then
n div:= 2;
else
n := 3*n + 1;
end if;
end loop;
return seq;
end proc;
end program;