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%I #16 Oct 19 2021 20:16:56
%S 5,8,13,16,21,25,28,33,37,40,46,50,54,59,62,66,71,74,78,83,86,90,97,
%T 100,106,110,114,119,122,126,131,134,138,143,146,150,157,160,166,170,
%U 174,179,182,186,191,194,198,203,206,210,218,222,227,230,234,239,242,246
%N Trajectory of 5 under repeated application of the map: n -> n + second-smallest number that does not divide n.
%H Robert Israel, <a href="/A140488/b140488.txt">Table of n, a(n) for n = 1..10000</a>
%F It appears that a(n+98) = a(n)+420 for n >= 9. - _Robert Israel_, Oct 19 2021
%p f:= proc(n) local k,c;
%p c:= 0:
%p for k from 2 do
%p if n mod k <> 0 then
%p if c = 1 then return n+k fi;
%p c:= 1;
%p fi
%p od
%p end proc:
%p R:= 5: t:= 5:
%p for count from 2 to 100 do
%p t:= f(t);
%p R:= R,t;
%p od:
%p R; # _Robert Israel_, Oct 19 2021
%t a = {5}; Do[AppendTo[a, a[[ -1]] + Select[Range[a[[ -1]]], Mod[a[[ -1]], # ] > 0 &][[2]]], {60}]; a (* _Stefan Steinerberger_, Jul 01 2008 *)
%o (Python)
%o def aupton(terms):
%o alst = [5]
%o while len(alst) < terms:
%o an, k, smallest = alst[-1], 2, False
%o while not smallest or an%k == 0:
%o if not smallest and an%k != 0: smallest = True
%o k += 1
%o alst.append(an+k)
%o return alst
%o print(aupton(58)) # _Michael S. Branicky_, Oct 19 2021
%Y Cf. A140485, A140486, A140487, A140489.
%K nonn
%O 1,1
%A _Eric Angelini_, Jun 25 2008
%E Corrected and extended by _Stefan Steinerberger_, Jul 01 2008
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