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A004773 Numbers congruent to {0, 1, 2} mod 4: a(n) = floor(4*n/3). 26
0, 1, 2, 4, 5, 6, 8, 9, 10, 12, 13, 14, 16, 17, 18, 20, 21, 22, 24, 25, 26, 28, 29, 30, 32, 33, 34, 36, 37, 38, 40, 41, 42, 44, 45, 46, 48, 49, 50, 52, 53, 54, 56, 57, 58, 60, 61, 62, 64, 65, 66, 68, 69, 70, 72, 73, 74, 76, 77, 78, 80, 81, 82, 84, 85, 86, 88, 89, 90 (list; graph; refs; listen; history; text; internal format)
OFFSET

0,3

COMMENTS

The sequence b(n) = floor((4/3)*(n+2)) appears as an upper bound in Fijavz and Wood.

Binary expansion does not end in 11.

LINKS

Table of n, a(n) for n=0..68.

Gasper Fijavz, David R. Wood, Graph Minors and Minimum Degree, arXiv:0812.1064 [math.CO], 2008.

N. Graham and F. Harary, Edge Sums of Hypercubes, Bull. Irish Math. Soc. 21 (1988), 8-12.

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

FORMULA

G.f.: (1+x+2*x^2)/((1-x)*(1-x^3)).

a(0) = 0, a(n+1) = a(n) + a(n) mod 4 + 0^(a(n) mod 4). - Reinhard Zumkeller, Mar 23 2003

a(n) = A004396(n) + A004523(n); complement of A004767. - Reinhard Zumkeller, Aug 29 2005

a(n) = floor(n/3) + n. - Gary Detlefs, Mar 20 2010

a(n) = (12*n-3+3*cos(2*n*Pi/3)+sqrt(3)*sin(2*n*Pi/3))/9. - Wesley Ivan Hurt, Sep 30 2017

MAPLE

seq(floor(n/3)+n, n=0..68); # Gary Detlefs, Mar 20 2010

MATHEMATICA

f[n_] := Floor[4 n/3]; Array[f, 69, 0] (* Robert G. Wilson v, Dec 24 2010 *)

fQ[n_] := Mod[n, 4] != 3; Select[ Range[0, 90], fQ] (* Robert G. Wilson v, Dec 24 2010 *)

a[0] = 0; a[n_] := a[n] = a[n - 1] + 2 - If[ Mod[a[n - 1], 4] < 2, 1, 0]; Array[a, 69, 0] (* Robert G. Wilson v, Dec 24 2010 *)

CoefficientList[ Series[x (1 + x + 2 x^2)/((1 - x) (1 - x^3)), {x, 0, 68}], x] (* Robert G. Wilson v, Dec 24 2010 *)

PROG

(MAGMA) [n: n in [0..100] | n mod 4 in [0..2]]; // Vincenzo Librandi, Dec 23 2010

(PARI) a(n)=4*n\3 \\ Charles R Greathouse IV, Sep 27 2012

CROSSREFS

Cf. A032766, this sequence, A001068, A047226, A047368, A004777.

Cf. similar sequences with formula n+i*floor(n/3) listed in A281899.

Sequence in context: A139255 A277676 A317551 * A104401 A184421 A039070

Adjacent sequences:  A004770 A004771 A004772 * A004774 A004775 A004776

KEYWORD

nonn,easy

AUTHOR

N. J. A. Sloane

STATUS

approved

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Last modified November 20 02:57 EST 2018. Contains 317371 sequences. (Running on oeis4.)