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A093390 a(n) = floor(n/9) + floor((n+1)/9) + floor((n+2)/9). 6
0, 0, 0, 0, 0, 0, 0, 1, 2, 3, 3, 3, 3, 3, 3, 3, 4, 5, 6, 6, 6, 6, 6, 6, 6, 7, 8, 9, 9, 9, 9, 9, 9, 9, 10, 11, 12, 12, 12, 12, 12, 12, 12, 13, 14, 15, 15, 15, 15, 15, 15, 15, 16, 17, 18, 18, 18, 18, 18, 18, 18, 19, 20, 21, 21, 21, 21, 21, 21, 21, 22, 23, 24, 24, 24, 24, 24, 24, 24, 25 (list; graph; refs; listen; history; text; internal format)
OFFSET
0,9
COMMENTS
Half the domination number of the camel's graph (from Tamerlane Chess) on a 2 X (n-6) chessboard. - David Nacin, May 28 2017
LINKS
FORMULA
G.f.: x^7 / ( (x^6+x^3+1)*(x-1)^2 ). - R. J. Mathar, Mar 22 2011
a(n) = n/3 + O(1). - Charles R Greathouse IV, Oct 16 2015
a(n) = A287394(n-6)/2. - David Nacin, May 28 2017
MATHEMATICA
Array[Total@ Map[Floor[#/9] &, # + Range[0, 2]] &, 80, 0] (* or *)
CoefficientList[Series[x^7/((x^6 + x^3 + 1) (x - 1)^2), {x, 0, 79}], x] (* Michael De Vlieger, Dec 12 2017 *)
PROG
(PARI) a(n)=n\9+(n+1)\9+(n+2)\9 \\ Charles R Greathouse IV, Oct 16 2015
CROSSREFS
Sequence in context: A069637 A072292 A243282 * A025789 A080585 A295977
KEYWORD
nonn,easy
AUTHOR
Reinhard Zumkeller, Mar 28 2004
STATUS
approved

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Last modified March 18 22:56 EDT 2024. Contains 370952 sequences. (Running on oeis4.)