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A037639
Base 4 digits are, in order, the first n terms of the periodic sequence with initial period 2,3,1.
1
2, 11, 45, 182, 731, 2925, 11702, 46811, 187245, 748982, 2995931, 11983725, 47934902, 191739611, 766958445, 3067833782, 12271335131, 49085340525, 196341362102, 785365448411, 3141461793645, 12565847174582, 50263388698331
OFFSET
1,1
FORMULA
G.f.: x*(x+2)*(1+x) / ( (x-1)*(4*x-1)*(1+x+x^2) ). - R. J. Mathar, Nov 21 2011
a(n) = 4*a(n-1) + a(n-3) - 4*a(n-4). - Vincenzo Librandi, Jun 17 2012
MATHEMATICA
LinearRecurrence[{4, 0, 1, -4}, {2, 11, 45, 182}, 40] (* Vincenzo Librandi, Jun 17 2012 *)
PROG
(Magma) I:=[2, 11, 45, 182]; [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: A209604 A120279 A037751 * A319428 A000176 A042927
KEYWORD
nonn,base
STATUS
approved