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 A053393 Periodic points under the map A053392 that adds consecutive pairs of digits and concatenates them. 3
 0, 991, 992, 993, 994, 995, 996, 997, 998, 999, 1810, 1811, 1812, 1813, 1814, 1815, 1816, 1817, 1818, 6664, 6665, 6666, 6667, 6668, 6669, 33331, 33332, 33333, 33334, 33335, 33336, 121210, 121211, 121212, 121213, 121214, 121215 (list; graph; refs; listen; history; text; internal format)
 OFFSET 0,2 COMMENTS Apart from 0, the terms listed so far are all of period 2 or 3. Are there longer periods? LINKS Table of n, a(n) for n=0..36. EXAMPLE f(84290) = 126119 since 8+4 = 12, 4+2 = 6, 2+9 = 11, 9+0 = 9. PROG (Python) def f(n): if 0 <= n <= 9: return 0 d = str(n) return int("".join(str(int(di)+int(dj)) for di, dj in zip(d[:-1], d[1:]))) def aupto(limit): n, DIVERGENCELIMIT = 0, 10**100 while n <= limit: m, orbit = n, [] while m <= DIVERGENCELIMIT and m not in orbit: orbit.append(m); m = f(m) if m in orbit and m == orbit[0]: print(n, end=", ") n += 1 aupto(130000) # Michael S. Branicky, Mar 24 2021 CROSSREFS Cf. A053392. Sequence in context: A119077 A119057 A218401 * A031790 A137703 A255098 Adjacent sequences: A053390 A053391 A053392 * A053394 A053395 A053396 KEYWORD nonn,base,nice,more AUTHOR Erich Friedman, Jan 07 2000 EXTENSIONS More terms from Naohiro Nomoto, Apr 06 2001 0 added by N. J. A. Sloane, Nov 01 2019 STATUS approved

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Last modified June 5 02:20 EDT 2023. Contains 363130 sequences. (Running on oeis4.)