A076635 Let b(1)=1/n, b(2)=1, b(k+1)=abs(b(k))-b(k-1)^2; then b(k) is >0 for k>a(n).

5, 8, 12, 11, 11, 15, 14, 14, 14, 18, 18, 17, 17, 17, 17, 17, 21, 20, 21, 21, 21, 20, 20, 20, 20, 20, 20, 20, 20, 20, 20, 20, 24, 24, 24, 24, 25, 23, 23, 23, 23, 23, 23, 23, 23, 23, 23, 23, 23, 23, 23, 23, 23, 23, 23, 28, 27, 27, 27, 27, 27, 27, 27, 28, 26, 26, 26, 26, 26, 26

Offset

1,1

Comments

Conjecture: lim k->infinity (b(k)-k)/log(k) = f(n), constant depending on n. f(n) seems erratic: f(2)=2.9..., f(3)=2.5..., f(4)=3.2..., f(5)=2.25..., f(6)=4.0...

Links

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

Formula

a(n) seems to be asymptotic to c*log(n) with c=5.63...

Example

If n=4, b(11)<0 and b(k)>0 for any k>11 hence a(4)=11.

Crossrefs

Sequence in context: A133269 A247245 A319675 * A294227 A116602 A079896

Adjacent sequences: A076632 A076633 A076634 * A076636 A076637 A076638

Keyword

nonn

Author

Benoit Cloitre, Oct 23 2002

Status

approved