A064289 Height of n-th term in Recamán's sequence A005132.
0, 1, 2, 3, 2, 3, 4, 5, 4, 5, 4, 5, 4, 5, 4, 5, 4, 5, 6, 7, 6, 7, 6, 5, 6, 5, 6, 5, 6, 5, 6, 5, 6, 7, 8, 7, 8, 7, 6, 7, 6, 7, 6, 7, 6, 7, 6, 7, 6, 7, 6, 7, 6, 7, 6, 7, 6, 7, 6, 7, 6, 7, 6, 7, 6, 7, 8, 9, 8, 9, 8, 9, 8, 9, 8, 9, 8, 7, 8, 7, 8, 7, 8, 7, 8, 7, 8, 7, 8, 7, 8, 7, 8, 7, 8, 7, 8, 7, 8, 7
Offset: 0
Examples
A005132 begins 1, 3, 6, 2, 7, 13, 20, 12, ... and these terms have heights 1, 2, 3, 2, 3, 4, 5, 4, ...
Links
- Alois P. Heinz, Table of n, a(n) for n = 0..100000
- Nick Hobson, Python program for this sequence
- N. J. A. Sloane, FORTRAN program for A005132, A057167, A064227, A064228
- Index entries for sequences related to Recamán's sequence
Programs
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Maple
g:= proc(n) is(n=0) end: b:= proc(n) option remember; local t; if n=0 then 0 else t:= b(n-1)-n; if t<=0 or g(t) then t:= b(n-1)+n fi; g(t):= true; t fi end: a:= proc(n) option remember; `if`(n=0, 0, a(n-1)+signum(b(n)-b(n-1))) end: seq(a(n), n=0..120); # Alois P. Heinz, Sep 08 2019 -
Mathematica
g[n_] := n == 0; b[n_] := b[n] = Module[{t}, If[n == 0, 0, t = b[n - 1] - n; If[t <= 0 || g[t], t = b[n - 1] + n]; g[t] = True; t]]; a[n_] := a[n] = If[n == 0, 0, a[n - 1] + Sign[b[n] - b[n - 1]]]; a /@ Range[0, 100] (* Jean-François Alcover, Apr 11 2020, after Alois P. Heinz *)
Extensions
a(0)=0 prepended by Allan C. Wechsler, Sep 08 2019
Comments