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 A070867 a(1) = a(2) = 1; a(n) = a(n-1 - a(n-1)) + a(n-1 - a(n-2)). 8
 1, 1, 2, 2, 2, 4, 3, 4, 4, 4, 8, 5, 5, 8, 8, 6, 8, 12, 8, 11, 9, 9, 10, 13, 16, 9, 12, 20, 10, 12, 23, 12, 15, 21, 13, 17, 18, 19, 19, 22, 21, 19, 19, 26, 28, 16, 24, 33, 21, 26, 23, 36, 16, 26, 39, 16, 30, 33, 36, 19, 34, 31, 43, 23, 30, 32, 38, 23, 40, 26, 38, 43, 31, 31, 38, 44 (list; graph; refs; listen; history; text; internal format)
 OFFSET 1,3 REFERENCES S. Wolfram, A New Kind of Science, Wolfram Media, 2002; p. 129. LINKS Reinhard Zumkeller, Table of n, a(n) for n = 1..10000 Nick Hobson, Python program for this sequence Eric Weisstein's World of Mathematics, Wolfram Sequences MATHEMATICA a[1] = a[2] = 1; a[n_] := a[n] = a[n - 1 - a[n - 1]] + a[n - 1 - a[n - 2]]; Table[ a[n], {n, 1, 80}] PROG (Haskell) a070867 n = a070867_list !! (n-1) a070867_list = 1 : 1 : zipWith (+)    (map a070867 \$ zipWith (-) [2..] a070867_list)    (map a070867 \$ zipWith (-) [2..] \$ tail a070867_list) -- Reinhard Zumkeller, May 31 2013 CROSSREFS Cf. A005185, A226222. Sequence in context: A166008 A194291 A194323 * A241164 A029157 A247301 Adjacent sequences:  A070864 A070865 A070866 * A070868 A070869 A070870 KEYWORD nonn,easy AUTHOR N. J. A. Sloane, May 19 2002 EXTENSIONS More terms from John W. Layman, May 21 2002 Erroneous comma in sequence corrected by Nick Hobson, Feb 17 2007 STATUS approved

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Last modified July 28 23:26 EDT 2021. Contains 346340 sequences. (Running on oeis4.)