A078117 Let u(1)=n, u(2)=n+1, v(1)=n+2, v(2)=n+3, u(k)=abs(u(k-1)-v(k-2)), v(k)=abs(v(k-1)-u(k-2)), then a(n) is the smallest integer such that for any k>=a(n), v(k)=u(k).

8, 11, 15, 17, 15, 10, 12, 14, 12, 14, 9, 14, 12, 17, 21, 23, 21, 16, 18, 20, 18, 20, 15, 20, 18, 23, 27, 29, 27, 22, 24, 26, 24, 26, 21, 26, 24, 29, 33, 35, 33, 28, 30, 32, 30, 32, 27, 32, 30, 35, 39, 41, 39, 34, 36, 38, 36, 38, 33, 38, 36, 41, 45, 47, 45, 40, 42, 44, 42, 44

Offset

1,1

Links

Table of n, a(n) for n=1..70.

Formula

a(n)/n -> 1/2.

For n >= 7, a(n) = (1/2)*(n+b(n-6)) where b(n) is the 12-periodic sequence (17, 20, 15, 18, 7, 16, 11, 20, 27, 30, 25, 14).

Crossrefs

Sequence in context: A029629 A028394 A188199 * A256073 A032423 A063724

Adjacent sequences: A078114 A078115 A078116 * A078118 A078119 A078120

Keyword

nonn

Author

Benoit Cloitre, Dec 05 2002

Extensions

a(6) and a(69) corrected by Sean A. Irvine, Jun 16 2025

Status

approved