login
The OEIS is supported by the many generous donors to the OEIS Foundation.

 

Logo
Hints
(Greetings from The On-Line Encyclopedia of Integer Sequences!)
A168093 a(n) = number of natural numbers m such that n - 3 <= m <= n + 3. 0
3, 4, 5, 6, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7 (list; graph; refs; listen; history; text; internal format)
OFFSET
0,1
COMMENTS
Generalization: If a(n,k) = number of natural numbers m such that n - k <= m <= n + k (k >= 1) then a(n,k) = a(n-1,k) + 1 = n + k for 0 <= n <= k, a(n,k) = a(n-1,k) = 2k + 1 for n >= k + 1 (see, e.g., A158799).
LINKS
FORMULA
a(n) = 3 + n for 0 <= n <= 3, a(n) = 7 for n >= 4.
G.f.: (3 - 2*x - x^5)/(1-x)^2. - G. C. Greubel, Jul 11 2016
MATHEMATICA
CoefficientList[Series[(3 - 2*x - x^5)/(1 - x)^2, {x, 0, 25}], x] (* G. C. Greubel, Jul 11 2016 *)
CROSSREFS
Cf. A000027.
Sequence in context: A245689 A182258 A067628 * A095254 A262980 A242374
KEYWORD
nonn,less
AUTHOR
Jaroslav Krizek, Nov 18 2009
STATUS
approved

Lookup | Welcome | Wiki | Register | Music | Plot 2 | Demos | Index | Browse | More | WebCam
Contribute new seq. or comment | Format | Style Sheet | Transforms | Superseeker | Recents
The OEIS Community | Maintained by The OEIS Foundation Inc.

License Agreements, Terms of Use, Privacy Policy. .

Last modified April 25 01:35 EDT 2024. Contains 371964 sequences. (Running on oeis4.)