Logo

Greetings from The On-Line Encyclopedia of Integer Sequences!

Hints

Search: id:A141525
Displaying 1-1 of 1 results found. page 1
     Format: long | short | internal | text      Sort: relevance | references | number      Highlight: on | off
A141525 A low average ratio switched sequence: a(n)=If[Mod[n, 3] == 0, a(n - 2) + a(n - 3), If(Mod[n, 4) == 0, a(n - 1) + a(n - 4), a(n - 1), a(n - 2)]]. +0
1
0, 1, 1, 1, 1, 1, 2, 2, 3, 4, 4, 4, 8, 8, 8, 16, 24, 24, 40, 40, 64, 80, 80, 80, 160, 160, 160, 320, 480, 480, 800, 800, 1280, 1600, 1600, 1600, 3200, 3200, 3200, 6400, 9600 (list; table; graph; listen)
OFFSET

1,7

COMMENT

While appearing to be an "even" output or maybe a "regular" sequence the average ratio limit( using <> as expectation value):

Limit[<a(n+1)/a(n)>,n->Infinity]=1.324717957244746;

real root of x^3-x-1 ( Padovan/ minimal Pisot root).

I got this by accident I meant to type in:

a[n] = If[Mod[n, 3] == 0, a[n - 2] + a[n - 3], If[Mod[n, 4] == 0, a[n - 1] + a[n - 4], a[n - 1] + a[n - 2]]];

which gives a different result!

REFERENCES

.

FORMULA

a(n)=If[Mod[n, 3] == 0, a(n - 2) + a(n - 3), If(Mod[n, 4) == 0, a(n - 1) + a(n - 4), a(n - 1), a(n - 2)]].

MATHEMATICA

Clear[a] a[0] = 0; a[1] = 1; a[2] = 1; a[3] = 1; a[n_] := a[n] = If[Mod[n, 3] == 0, a[n - 2] + a[n - 3], If[Mod[n, 4] == 0, a[n - 1] + a[n - 4], a[n - 1], a[n - 2]]]; Table[a[n], {n, 0, 40}]

CROSSREFS

Sequence in context: A070172 A130128 A049980 this_sequence A071475 A112778 A080594

Adjacent sequences: A141522 A141523 A141524 this_sequence A141526 A141527 A141528

KEYWORD

nonn,uned,tabl

AUTHOR

Roger L. Bagula (rlbagulatftn(AT)yahoo.com), Aug 11 2008

page 1

Search completed in 0.002 seconds

Lookup | Welcome | Find friends | Music | Plot 2 | Demos | Index | Browse | More | WebCam
Contribute new seq. or comment | Format | Transforms | Puzzles | Hot | Classics
More pages | Superseeker | Maintained by N. J. A. Sloane (njas@research.att.com)

Last modified November 25 08:46 EST 2009. Contains 167481 sequences.


AT&T Labs Research