OFFSET
0,2
COMMENTS
The increasing complementary sequences a() and b() are uniquely determined by the titular equation and initial values; a(n)/a(n-1) -> (1 + sqrt(5))/2, the golden ratio (A001622).
LINKS
Clark Kimberling, Table of n, a(n) for n = 0..1000
EXAMPLE
a(0) = 1, a(1) = 2, a(2) = 3, b(0)= 4, b(1) = 5, b(2) = 6; b(3) = 7, and a(3) = 2*3 - 1 + 7 = 12.
MATHEMATICA
a[0] = 1; a[1] = 2; a[2] = 3; b[0] = 4; b[1] = 5; b[2] = 6; b[3] = 7;
a[n_] := a[n] = 2*a[n - 1] - a[n - 3] + b[n];
j = 1; While[j < 12, k = a[j] - j - 1;
While[k < a[j + 1] - j + 1, b[k] = j + k + 2; k++]; j++];
Table[a[n], {n, 0, 60}] (* A305746 *)
CROSSREFS
KEYWORD
nonn,easy
AUTHOR
Clark Kimberling, Jun 10 2018
STATUS
approved