OFFSET
1,1
COMMENTS
This is one of four sequences that partition the positive integers.
Given t is the tetranacci constant, then the following sequences are disjoint:
. A184823(n) = n + [n/t] + [n/t^2] + [n/t^3],
. A184824(n) = n + [n*t] + [n/t] + [n/t^2],
. A184825(n) = n + [n*t] + [n*t^2] + [n/t],
. A184826(n) = n + [n*t] + [n*t^2] + [n*t^3], where []=floor.
This is a special case of Clark Kimberling's results given in A184812.
FORMULA
Lim_{n->infinity} a(n)/n = t^3 = 7.1618472084864470579236869...
a(n) = n + floor(n*p/q) + floor(n*r/q) + floor(n*s/q), where p=t, q=t^2, r=t^3, s=t^4, and t is the tetranacci constant.
EXAMPLE
Let t be the tetranacci constant, then t^3 = 1 + t + t^2 + 1/t and:
t = 1.92756197548..., t^2 = 3.71549516932..., t^3 = 7.16184720848..., t^4 = 13.8049043532...
MATHEMATICA
With[{t=x/.Last[Solve[x^4==Total[x^Range[0, 3]], x]]}, Table[n+Floor[n t]+Floor[n t^2]+Floor[n/t], {n, 120}]] (* Harvey P. Dale, Feb 02 2011 *)
PROG
(PARI) {a(n)=local(t=real(polroots(1+x+x^2+x^3-x^4)[2])); n+floor(n*t)+floor(n*t^2)+floor(n/t)}
CROSSREFS
KEYWORD
nonn
AUTHOR
Paul D. Hanna, Jan 23 2011
STATUS
approved