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A068915 a(n) = n if n<2; a(n) = |a(n/2)-a(n/2-1)| if n is even, and a(n) = a((n-1)/2) + a((n-1)/2+1) if n is odd. 1
0, 1, 1, 2, 0, 3, 1, 2, 2, 3, 3, 4, 2, 3, 1, 4, 0, 5, 1, 6, 0, 7, 1, 6, 2, 5, 1, 4, 2, 5, 3, 4, 4, 5, 5, 6, 4, 7, 5, 6, 6, 7, 7, 8, 6, 7, 5, 8, 4, 7, 3, 6, 4, 5, 3, 6, 2, 7, 3, 8, 2, 7, 1, 8, 0, 9, 1, 10, 0, 11, 1, 10, 2, 11, 3, 12, 2, 11, 1, 12, 0, 13, 1, 14, 0, 15, 1, 14, 2, 13, 1, 12, 2, 13, 3, 12, 4, 11, 3, 10, 4, 9, 3, 10, 2, 9, 1, 8, 2, 9, 3, 8, 4, 9, 5, 10, 4, 11, 5, 10 (list; graph; refs; listen; history; text; internal format)
OFFSET
0,4
LINKS
EXAMPLE
a(2) = |1-0| = 1, a(3) = 1+1 = 2, a(4) = |1-1| = 0, a(5) = 1+2 = 3.
MAPLE
a:= proc(n) option remember;
if n<2 then n
elif irem (n, 2)=0 then abs(a(n/2)-a(n/2-1))
else a((n-1)/2)+a((n-1)/2+1)
fi
end:
seq (a(n), n=0..119);
MATHEMATICA
a[n_] := a[n] = If[n<2, n, If[EvenQ[n], Abs[a[n/2] - a[n/2-1]], a[(n-1)/2] + a[(n-1)/2 + 1]]];
a /@ Range[0, 119] (* Jean-François Alcover, Nov 17 2020 *)
CROSSREFS
Sequence in context: A080096 A322978 A294142 * A302193 A133925 A071492
KEYWORD
easy,nonn
AUTHOR
Aaron K. Johnson (akj(AT)21stcentury.net), Mar 06 2002
EXTENSIONS
Edited by Alois P. Heinz, Feb 04 2011
STATUS
approved

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Last modified April 13 10:11 EDT 2024. Contains 371640 sequences. (Running on oeis4.)