A173633 a(n) = a(n-2) + a(n-3) - [a(n-3)/4] - [a(n-4)/2] - [a(n-5)/4].

1, 1, 1, 2, 2, 3, 4, 4, 6, 6, 7, 8, 8, 10, 10, 11, 12, 12, 14, 14, 15, 16, 16, 18, 18, 19, 20, 20, 22, 22, 23, 24, 24, 26, 26, 27, 28, 28, 30, 30, 31, 32, 32, 34, 34, 35, 36, 36, 38, 38, 39

Offset

0,4

Comments

The limiting ratio a(n+1)/a(n) goes very near one in two alternating modes.

Links

Table of n, a(n) for n=0..50.

Formula

a(n)=a(n-2)+a(n-3)-Floor[a(n-3)/4]-Floor[a(n-4)/2]-Floor[a(n-5)/4]

Mathematica

f[-3] = 0; f[-2] = 0; f[-1] = 0; f[0] = 1; f[1] = 1;
f[n_] := f[n] = f[n - 2] + f[n - 3] - Floor[f[n - 3]/
4] - Floor[f[n - 4]/2] - Floor[f[n - 5]/4]
Table[f[n], {n, 0, 50}]

Crossrefs

Sequence in context: A211317 A126246 A338517 * A138369 A173332 A348526

Adjacent sequences: A173630 A173631 A173632 * A173634 A173635 A173636

Keyword

nonn

Author

Roger L. Bagula, Nov 23 2010

Status

approved