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 A232271 Start with positive integers (A000027), and at each step n >= 1 subtract from the term at position n + a(n) the value a(n). 0
 1, 1, 2, 4, 3, 6, 7, 1, 8, 10, 11, 6, 13, 7, 15, 16, 9, 12, 30, 10, 14, 11, 23, 24, 25, 4, 27, 28, 29, -11, 31, 16, 22, 34, 21, 36, 37, 19, 39, 40, 41, 42, 43, 44, 45, 23, 47, 8, 49, 25, 51, 52, 53, 27, 34, -1, 38, 29, 59, 60, 61, 31, 63, 64, 65, 66, 67, 34, 307, 70, 71 (list; graph; refs; listen; history; text; internal format)
 OFFSET 1,3 COMMENTS The first 71 terms are correct if the following conjecture is true: n+a(n)<=0 or n+a(n)>71 for n >= 2^30. The sequence of negative terms begins: -11, -1, -261, -11, -253, -319, -341, -407, -451, -528, -329, -371, -29, -31, -649, -619, -427, -737, -37, ... Indices of negative terms: 30, 56, 330, 616, 690, 870, 930, 1110, 1230, 1288, 1410, 1590, 1624, 1736, 1770, 1820, 1830, 2010, 2072, ... Numbers n such that a(n)=n: 1, 4, 6, 7, 10, 11, 13, 15, 16, 23, 24, 25, 27, 28, 29, 31, 34, 36, 37, 39, 40, 41, 42, 43, 44, 45, ... The sequence of numbers n such that n+a(n)<0 begins: 1485264, 2029290, 6156150, 6872250, 8338512, 8769090, 10420410, 13448490, 16654110, 25894770, ... LINKS PROG (Python) TOP = 2**30  # if enough RAM a = [1]*TOP for n in range(1, TOP):   a[n]=n for n in range(1, TOP):   if n+a[n]0: a[n+a[n]] -= a[n] for n in range(1, 1000):   print str(a[n])+', ', CROSSREFS Cf. A000027, A136119, A137319, A137417, A137418, A137894. Sequence in context: A235451 A039819 A242424 * A194277 A226246 A216623 Adjacent sequences:  A232268 A232269 A232270 * A232272 A232273 A232274 KEYWORD sign AUTHOR Alex Ratushnyak, Nov 22 2013 EXTENSIONS Corrected by Alex Ratushnyak, Dec 28 2013 STATUS approved

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Last modified March 18 13:47 EDT 2019. Contains 321289 sequences. (Running on oeis4.)