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A187321 a(n) = floor(n/2) + floor(n/4). 0
0, 0, 1, 1, 3, 3, 4, 4, 6, 6, 7, 7, 9, 9, 10, 10, 12, 12, 13, 13, 15, 15, 16, 16, 18, 18, 19, 19, 21, 21, 22, 22, 24, 24, 25, 25, 27, 27, 28, 28, 30, 30, 31, 31, 33, 33, 34, 34, 36, 36, 37, 37, 39, 39, 40, 40, 42, 42, 43, 43, 45, 45, 46, 46, 48, 48, 49, 49, 51, 51, 52, 52, 54 (list; graph; refs; listen; history; text; internal format)
OFFSET

0,5

LINKS

Table of n, a(n) for n=0..72.

Index entries for linear recurrences with constant coefficients, signature (1,0,0,1,-1)

FORMULA

a(n) = floor(n/2) + floor(n/4).

G.f.: x^2*(1+2*x^2)/((1+x)*(x^2+1)*(x-1)^2). - R. J. Mathar, Mar 08 2011

a(n) = A032766(floor(n/2)). - Bruno Berselli, Mar 08 2011

a(n) = (6*n-5+2*cos(n*Pi/2)+3*cos(n*Pi)+2*sin(n*Pi/2))/8. - Wesley Ivan Hurt, Oct 02 2017

MATHEMATICA

Table[Floor[n/2]+Floor[n/4], {n, 0, 120}]

CROSSREFS

Cf. A032766.

Sequence in context: A083522 A108942 A025561 * A145814 A198465 A292836

Adjacent sequences:  A187318 A187319 A187320 * A187322 A187323 A187324

KEYWORD

nonn,easy

AUTHOR

Clark Kimberling, Mar 08 2011

STATUS

approved

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Last modified May 21 11:54 EDT 2019. Contains 323443 sequences. (Running on oeis4.)