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 A324668 Starting at n, a(n) is the minimum positive point visited, or zero if no positive points are visited, according to the following rules. On the k-th step (k=1,2,3,...) move a distance of k in the direction of zero. If the number landed on has been landed on before, move a distance of k away from zero instead. 0
 0, 1, 1, 2, 1, 1, 3, 1, 2, 1, 4, 1, 1, 1, 4, 5, 1, 1, 3, 1, 1, 6, 1, 2, 1, 1, 5, 1, 7, 1, 1, 2, 3, 1, 1, 7, 8, 1, 1, 2, 3, 5, 6, 1, 1, 9, 1, 2, 1, 4, 1, 1, 7, 8, 1, 10, 1, 2, 3, 1, 2, 1, 1, 1, 9, 10, 11, 1, 1, 1, 4, 5, 6, 7, 1, 9, 1, 1, 12, 1, 2, 3, 4, 5, 6, 1 (list; graph; refs; listen; history; text; internal format)
 OFFSET 0,4 LINKS EXAMPLE For n=2, the points visited are 2,1,-1,-4,0.  As 1 is the smaller of the two positive values, a(2) = 1. PROG (Python) #Sequences A324660-A324692 generated by manipulating this trip function #spots - positions in order with possible repetition #flee - positions from which we move away from zero with possible repetition #stuck - positions from which we move to a spot already visited with possible repetition def trip(n):     stucklist = list()     spotsvisited = [n]     leavingspots = list()     turn = 0     forbidden = {n}     while n != 0:         turn += 1         sign = n // abs(n)         st = sign * turn         if n - st not in forbidden:             n = n - st         else:             leavingspots.append(n)             if n + st in forbidden:                 stucklist.append(n)             n = n + st         spotsvisited.append(n)         forbidden.add(n)     return {'stuck':stucklist, 'spots':spotsvisited,                 'turns':turn, 'flee':leavingspots} def minorzero(x):     if x:         return min(x)     return 0 #Actual sequence def a(n):     d = trip(n)     return minorzero([i for i in d['spots'] if i > 0]) CROSSREFS Cf. A228474, A324660-A324692. Sequence in context: A127704 A307662 A050873 * A128221 A327856 A175488 Adjacent sequences:  A324665 A324666 A324667 * A324669 A324670 A324671 KEYWORD nonn AUTHOR David Nacin, Mar 10 2019 STATUS approved

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Last modified September 26 20:36 EDT 2020. Contains 337374 sequences. (Running on oeis4.)