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A072515
Let u(1) = u(2) = v(1) = v(2) = 1, u(n+2) = u(n)+v(n+1), v(n+2) = abs(u(n)-v(n+1)), then a(n) = u(n).
1
1, 1, 2, 1, 3, 2, 3, 5, 4, 7, 7, 8, 13, 9, 20, 15, 23, 32, 25, 53, 36, 67, 75, 70, 139, 81, 198, 161, 199, 358, 235, 521, 430, 561, 911, 612, 1421, 1013, 1632, 2223, 1829, 3658, 2617, 4699, 5234, 4699, 9933, 5234, 14097, 11003, 14632, 24565, 17191, 36638
OFFSET
1,3
COMMENTS
For any initial values u(1), v(1), u(2), v(2), it seems that lim n ->infinity log(a(n))/n = C = 0.192...
MATHEMATICA
a[1] = a[2] = v[1] = v[2] = 1; a[n_] := a[n] = a[n-2] + v[n-1]; v[n_] := v[n] = Abs[a[n-2] - v[n-1]];
Array[a, 100] (* Paolo Xausa, Oct 08 2024 *)
CROSSREFS
Sequence in context: A183163 A338359 A122545 * A318747 A297367 A118010
KEYWORD
easy,nonn
AUTHOR
Benoit Cloitre, Aug 04 2002
EXTENSIONS
Name corrected by Sean A. Irvine, Oct 07 2024
STATUS
approved