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 A194222 a(n) = floor(Sum_{k=1..n} frac(k/5)), where frac() = fractional part. 2
 0, 0, 1, 2, 2, 2, 2, 3, 4, 4, 4, 4, 5, 6, 6, 6, 6, 7, 8, 8, 8, 8, 9, 10, 10, 10, 10, 11, 12, 12, 12, 12, 13, 14, 14, 14, 14, 15, 16, 16, 16, 16, 17, 18, 18, 18, 18, 19, 20, 20, 20, 20, 21, 22, 22, 22, 22, 23, 24, 24, 24, 24, 25, 26, 26, 26, 26, 27, 28, 28, 28, 28, 29, 30 (list; graph; refs; listen; history; text; internal format)
 OFFSET 1,4 LINKS G. C. Greubel, Table of n, a(n) for n = 1..5000 Index entries for linear recurrences with constant coefficients, signature (1,0,0,0,1,-1). FORMULA From Chai Wah Wu, Jun 10 2020: (Start) a(n) = a(n-1) + a(n-5) - a(n-6) for n > 6. G.f.: x^3*(x + 1)/(x^6 - x^5 - x + 1). (End) a(n) = floor((n+1)/5) + floor((n+2)/5). - Ridouane Oudra, Dec 14 2021 MAPLE seq(floor((n+1)/5)+floor((n+2)/5), n=1..80); # Ridouane Oudra, Dec 14 2021 MATHEMATICA r = 1/5; a[n_] := Floor[Sum[FractionalPart[k*r], {k, 1, n}]] Table[a[n], {n, 1, 90}] (* A194222 *) s[n_] := Sum[a[k], {k, 1, n}] Table[s[n], {n, 1, 100}] (* A118015 *) CROSSREFS Cf. A118015. Sequence in context: A261221 A080352 A301426 * A025779 A085003 A119026 Adjacent sequences: A194219 A194220 A194221 * A194223 A194224 A194225 KEYWORD nonn,easy AUTHOR Clark Kimberling, Aug 19 2011 STATUS approved

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Last modified September 29 18:47 EDT 2023. Contains 365775 sequences. (Running on oeis4.)