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 A037101 Trajectory of 3 under map n->7n+1 if n odd, n->n/2 if n even. 2
 3, 22, 11, 78, 39, 274, 137, 960, 480, 240, 120, 60, 30, 15, 106, 53, 372, 186, 93, 652, 326, 163, 1142, 571, 3998, 1999, 13994, 6997, 48980, 24490, 12245, 85716, 42858, 21429, 150004, 75002, 37501, 262508, 131254, 65627, 459390, 229695, 1607866, 803933 (list; graph; refs; listen; history; text; internal format)
 OFFSET 0,1 LINKS Robert Israel, Table of n, a(n) for n = 0..10000 MAPLE a:= proc(n) option remember; local v; v:= procname(n-1); if v::odd then 7*v+1 else v/2 fi end proc: a(0):= 3: map(a, [\$0..100]); # Robert Israel, Jan 24 2020 MATHEMATICA nxt[n_]:=If[OddQ[n], 7n+1, n/2]; NestList[nxt, 3, 40] (* Harvey P. Dale, Jun 05 2012 *) PROG (Python) def iter(n): return 7*n+1 if n%2 == 1 else n//2 def aupton(terms): alst = [3] for n in range(1, terms+1): alst.append(iter(alst[-1])) return alst print(aupton(43)) # Michael S. Branicky, Mar 22 2021 CROSSREFS Cf. A063871. Sequence in context: A161377 A122495 A100977 * A226028 A248626 A360366 Adjacent sequences: A037098 A037099 A037100 * A037102 A037103 A037104 KEYWORD nonn AUTHOR N. J. A. Sloane. STATUS approved

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Last modified June 6 20:05 EDT 2023. Contains 363151 sequences. (Running on oeis4.)