login
The OEIS Foundation is supported by donations from users of the OEIS and by a grant from the Simons Foundation.

 

Logo


Hints
(Greetings from The On-Line Encyclopedia of Integer Sequences!)
A168097 a(n) = number of natural numbers m such that n - 7 <= m <= n + 7. 0
7, 8, 9, 10, 11, 12, 13, 14, 15, 15, 15, 15, 15, 15, 15, 15, 15, 15, 15, 15, 15, 15, 15, 15, 15, 15, 15, 15, 15, 15, 15, 15, 15, 15, 15, 15, 15, 15, 15, 15, 15, 15, 15, 15, 15, 15, 15, 15, 15, 15, 15, 15, 15, 15, 15 (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

Table of n, a(n) for n=0..54.

FORMULA

a(n) = 7 + n for 0 <= n <= 7, a(n) = 15 for n >= 8.

G.f.: (7 - 6*x - x^9)/(1-x)^2. - G. C. Greubel, Jul 12 2016

MATHEMATICA

CoefficientList[Series[(7 - 6*x - x^9)/(1 - x)^2, {x, 0, 25}], x] (* G. C. Greubel, Jul 12 2016 *)

CROSSREFS

Cf. A000027.

Sequence in context: A196278 A006969 A195935 * A020719 A162787 A182308

Adjacent sequences:  A168094 A168095 A168096 * A168098 A168099 A168100

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 | Recent
The OEIS Community | Maintained by The OEIS Foundation Inc.

License Agreements, Terms of Use, Privacy Policy. .

Last modified May 25 07:56 EDT 2020. Contains 334585 sequences. (Running on oeis4.)