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A037604 Base-4 digits are, in order, the first n terms of the periodic sequence with initial period 1,2,3. 0
1, 6, 27, 109, 438, 1755, 7021, 28086, 112347, 449389, 1797558, 7190235, 28760941, 115043766, 460175067, 1840700269, 7362801078, 29451204315, 117804817261, 471219269046, 1884877076187, 7539508304749, 30158033218998 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,2

COMMENTS

Convolution of A000302 with A010882. - Philippe Deléham, Mar 24 2013

LINKS

Table of n, a(n) for n=1..23.

Index entries for linear recurrences with constant coefficients, signature (4,0,1,-4).

Index entries for 2-automatic sequences.

FORMULA

G.f.: x*(1+2x+3*x^2)/((1-x)*(1-4x)*(1+x+x^2)). - Philippe Deléham, Mar 24 2013

a(n) = 4*a(n-1) + a(n-3) -4*a(n-4) for n>5, a(1) = 1, a(2) = 6, a(3) = 27, a(4) = 109, a(5) = 438. - Philippe Deléham, Mar 24 2013

a(n+2) = 6*A033140(n) + A191597(n+2). - Philippe Deléham, Mar 24 2013

A007090(a(n)) = A037610(n). R. J. Mathar, Apr 27 2015

PROG

(PARI) a(n)=([0, 1, 0, 0; 0, 0, 1, 0; 0, 0, 0, 1; -4, 1, 0, 4]^(n-1)*[1; 6; 27; 109])[1, 1] \\ Charles R Greathouse IV, Feb 13 2017

CROSSREFS

Cf. A000302, A010882.

Sequence in context: A318638 A094829 A055145 * A022634 A094788 A221863

Adjacent sequences:  A037601 A037602 A037603 * A037605 A037606 A037607

KEYWORD

nonn,base,easy

AUTHOR

Clark Kimberling

STATUS

approved

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Last modified February 17 14:37 EST 2019. Contains 320220 sequences. (Running on oeis4.)