A285202 -id:A285202 - cp's OEIS frontend

A285204 Row lengths of triangle A285202.

1, 3, 5, 5, 7, 5, 7, 5, 7, 5, 9, 5, 7, 5, 7, 5, 9, 5, 7, 5, 7, 5, 9, 5, 7, 5, 7, 5, 9, 5, 7, 5, 7, 5, 11, 5, 7, 5, 7, 5, 9, 5, 7, 5, 7, 5, 9, 5, 7, 5, 7, 5, 9, 5, 7, 5, 7, 5, 11, 5, 7, 5, 7, 5, 9, 5, 7, 5, 7, 5, 9, 5, 7, 5, 7, 5, 9, 5, 7, 5, 7, 5, 11, 5, 7, 5, 7, 5, 9, 5, 7

Offset: 0

N. J. A. Sloane, May 03 2017

nonn

Cf. A285200-A285203.

a(n) = 2*A285203(n)-1 for n>0.

A285200 a(n) = floor the elevator is on at the n-th stage of Ken Knowlton's elevator problem, version 1.

Original entry on oeis.org

1, 2, 1, 2, 3, 2, 1, 2, 3, 2, 1, 2, 3, 4, 3, 2, 1, 2, 3, 2, 1, 2, 3, 4, 3, 2, 1, 2, 3, 2, 1, 2, 3, 4, 3, 2, 1, 2, 3, 2, 1, 2, 3, 4, 5, 4, 3, 2, 1, 2, 3, 2, 1, 2, 3, 4, 3, 2, 1, 2, 3, 2, 1, 2, 3, 4, 3, 2, 1, 2, 3, 2, 1, 2, 3, 4, 5, 4, 3, 2, 1, 2, 3, 2, 1, 2, 3, 4, 3, 2, 1, 2, 3, 2, 1, 2, 3, 4, 3, 2, 1

Offset: 1

N. J. A. Sloane, May 02 2017

nonn

An elevator steps up or down a floor at a time. It starts at floor 1, and always goes up from floor 1. From each floor m, it steps up every m-th time it stops there, otherwise down.

See A285202 for an alternative way to display this sequence.

Ken Knowlton, Email to R. L. Graham, Apr 26 2017

N. J. A. Sloane, Table of n, a(n) for n = 1..20000
Ken Knowlton, Illustration showing what floor the elevator is on for the first 49 stages

Cf. A285201, A285202, A285203.

See A286281 for a second version of the elevator problem.

hit:=Array(1..50,0);
hit[1]:=1; a:=[1]; dir:=1; f:=1;
for s from 2 to 1000 do
if dir>0 then f:=f+1; else f:=f-1; fi;
hit[f]:=hit[f]+1; a:=[op(a),f];
if (hit[f] mod f) = 0 then dir:=1; else dir:=-1; fi;
od:
a;

cp's OEIS Frontend

A285204 Row lengths of triangle A285202.

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A285200 a(n) = floor the elevator is on at the n-th stage of Ken Knowlton's elevator problem, version 1.

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