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 A001042 a(n) = a(n-1)^2 - a(n-2)^2. (Formerly M0743 N0279) 3
 1, 2, 3, 5, 16, 231, 53105, 2820087664, 7952894429824835871, 63248529811938901240357985099443351745, 4000376523371723941902615329287219027543200136435757892789536976747706216384 (list; graph; refs; listen; history; text; internal format)
 OFFSET 0,2 COMMENTS The next term has 152 digits. - Franklin T. Adams-Watters, Jun 11 2009 REFERENCES Archimedeans Problems Drive, Eureka, 27 (1964), 6. N. J. A. Sloane, A Handbook of Integer Sequences, Academic Press, 1973 (includes this sequence). N. J. A. Sloane and Simon Plouffe, The Encyclopedia of Integer Sequences, Academic Press, 1995 (includes this sequence). LINKS Reinhard Zumkeller, Table of n, a(n) for n = 0..13 A. V. Aho and N. J. A. Sloane, Some doubly exponential sequences, Fib. Quart., 11 (1973), 429-437. R. K. Guy, Letters to N. J. A. Sloane, June-August 1968 R. P. Loh, A. G. Shannon, A. F. Horadam, Divisibility Criteria and Sequence Generators Associated with Fermat Coefficients, Preprint, 1980. FORMULA a(n) ~ c^(2^n), where c = 1.1853051643868354640833201434870139866230288004895868726506278977814490371... . - Vaclav Kotesovec, Dec 17 2014 MATHEMATICA RecurrenceTable[{a[0]==1, a[1]==2, a[n]==a[n-1]^2-a[n-2]^2}, a, {n, 0, 12}] (* Harvey P. Dale, Jan 11 2013 *) PROG (Haskell) a001042 n = a001042_list !! n a001042_list = 1 : 2 : zipWith (-) (tail xs) xs                where xs = map (^ 2) a001042_list -- Reinhard Zumkeller, Dec 16 2013 CROSSREFS Cf. A001146, A000278, A000283, A058182, A007018. Cf. A064236 (numbers of digits). Sequence in context: A192648 A219339 A048112 * A214697 A035089 A045313 Adjacent sequences:  A001039 A001040 A001041 * A001043 A001044 A001045 KEYWORD nonn,nice,easy AUTHOR EXTENSIONS More terms from James A. Sellers, Sep 19 2000 STATUS approved

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Last modified May 26 22:58 EDT 2020. Contains 334634 sequences. (Running on oeis4.)