A152890 - OEIS

A152890

Periodic sequence [4,1,4,0,1] of period 5

4, 1, 4, 0, 1, 4, 1, 4, 0, 1, 4, 1, 4, 0, 1, 4, 1, 4, 0, 1, 4, 1, 4, 0, 1, 4, 1, 4, 0, 1, 4, 1, 4, 0, 1, 4, 1, 4, 0, 1, 4, 1, 4, 0, 1, 4, 1, 4, 0, 1, 4, 1, 4, 0, 1

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OFFSET

0,1

LINKS

Table of n, a(n) for n=0..54.

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

FORMULA

a(n+5) = a(n).

G.f: (4+z+4*z^2+z^4)/(1-z^5).

a(n) = 2+(-1/5*5^(1/2)+1)*cos(2*n*Pi/5)+(2/5*2^(1/2)*(5-5^(1/2))^(1/2))*sin(2*n*Pi/5)+(1/5*5^(1/2)+1)*cos(4*n*Pi/5)+(-2/5*2^(1/2)*(5+5^(1/2))^(1/2))*sin(4*n*Pi/5)

CROSSREFS

Cf. A026051.

Sequence in context: A064221 A229672 A298568 * A143354 A324026 A171539

Adjacent sequences: A152887 A152888 A152889 * A152891 A152892 A152893

KEYWORD

easy,nonn,less

AUTHOR

Richard Choulet, Dec 14 2008

STATUS

approved