login
This site is supported by donations to The OEIS Foundation.

 

Logo


Hints
(Greetings from The On-Line Encyclopedia of Integer Sequences!)
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

Table of n, a(n) for n=0..47.

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

Lookup | Welcome | Wiki | Register | Music | Plot 2 | Demos | Index | Browse | More | WebCam
Contribute new seq. or comment | Format | Style Sheet | Transforms | Superseeker | Recent
The OEIS Community | Maintained by The OEIS Foundation Inc.

License Agreements, Terms of Use, Privacy Policy. .

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