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A037569 Base 4 digits are, in order, the first n terms of the periodic sequence with initial period 2,1,2. 1
2, 9, 38, 154, 617, 2470, 9882, 39529, 158118, 632474, 2529897, 10119590, 40478362, 161913449, 647653798, 2590615194, 10362460777, 41449843110, 165799372442, 663197489769, 2652789959078, 10611159836314, 42444639345257 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,1

LINKS

Vincenzo Librandi, Table of n, a(n) for n = 1..1000

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

FORMULA

G.f. x*(2+x+2*x^2) / ((x-1)*(4*x-1)*(1+x+x^2)). - R. J. Mathar, Nov 21 2011

a(n) = 4*(n-1) + a(n-3) - 4*a(n-4). Vincenzo Librandi, Jun 17 2012

MATHEMATICA

With[{c=PadRight[{}, 30, {2, 1, 2}]}, Table[FromDigits[Take[c, n], 4], {n, 30}]] (* Harvey P. Dale, Nov 06 2011 *)

LinearRecurrence[{4, 0, 1, -4}, {2, 9, 38, 154}, 40] (* Vincenzo Librandi, Jun 17 2012 *)

PROG

(MAGMA) I:=[2, 9, 38, 154]; [n le 4 select I[n] else 4*Self(n-1)+Self(n-3)-4*Self(n-4): n in [1..30]]; // Vincenzo Librandi, Jun 17 2012

CROSSREFS

Sequence in context: A181339 A291265 A037489 * A291462 A001077 A150993

Adjacent sequences:  A037566 A037567 A037568 * A037570 A037571 A037572

KEYWORD

nonn,base

AUTHOR

Clark Kimberling

STATUS

approved

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Last modified February 21 19:49 EST 2018. Contains 299423 sequences. (Running on oeis4.)