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A168098 a(n) = number of natural numbers m such that n - 8 <= m <= n + 8. 0
8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 17, 17, 17, 17, 17, 17, 17, 17, 17, 17, 17, 17, 17, 17, 17, 17, 17, 17, 17, 17, 17, 17, 17, 17, 17, 17, 17, 17, 17, 17, 17, 17, 17, 17, 17, 17, 17, 17, 17, 17, 17, 17, 17, 17, 17, 17, 17, 17 (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..57.

FORMULA

a(n) = 8 + n for 0 <= n <= 8, a(n) = 17 for n >= 9.

G.f.: (8 - 7*x - x^10)/(1 - x)^2. - G. C. Greubel, Jul 12 2016

MATHEMATICA

CoefficientList[Series[(8 - 7*x - x^10)/(1 - x)^2, {x, 0, 25}], x] (* G. C. Greubel, Jul 12 2016 *)

CROSSREFS

Cf. A000027.

Sequence in context: A217292 A004164 A004449 * A020722 A046037 A089017

Adjacent sequences:  A168095 A168096 A168097 * A168099 A168100 A168101

KEYWORD

nonn,less

AUTHOR

Jaroslav Krizek, Nov 18 2009

STATUS

approved

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Last modified August 7 19:57 EDT 2020. Contains 336279 sequences. (Running on oeis4.)