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, 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...

Links

Paolo Xausa, Table of n, a(n) for n = 1..1000

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

Adjacent sequences: A072512 A072513 A072514 * A072516 A072517 A072518

Keyword

easy,nonn,changed

Author

Benoit Cloitre, Aug 04 2002

Extensions

Name corrected by Sean A. Irvine, Oct 07 2024

Status

approved