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 A324673 Starting at n, a(n) is the length of the smallest interval containing all points 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 0
 0, 1, 6, 3, 68, 72, 6, 13205, 31, 36, 10, 104, 836, 836, 43, 15, 570, 9518374, 57, 60, 1548481, 21, 203, 80, 87, 15466141, 71, 71, 28, 2436, 118129102, 6815959, 6815959, 6815959, 6815959, 86, 36, 560, 2261901, 2261901, 1091, 103, 103, 103, 6831, 45, 758, 499 (list; graph; refs; listen; history; text; internal format)
 OFFSET 0,3 LINKS EXAMPLE For n=2, the points visited are 2,1,-1,-4,0.  The smallest interval containing these is [-4,2] which has length 6, thus a(2) = 6. 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} #Actual sequence def a(n):     d=trip(n)     return max(d['spots'])-min(d['spots']) CROSSREFS Cf. A228474, A324660-A324692. Equals A248953 - A248952. Sequence in context: A088390 A286782 A054380 * A324004 A002610 A100979 Adjacent sequences:  A324668 A324671 A324672 * A324674 A324675 A324676 KEYWORD nonn AUTHOR David Nacin, Mar 10 2019 STATUS approved

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Last modified August 18 15:00 EDT 2019. Contains 326106 sequences. (Running on oeis4.)