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%I #19 Aug 28 2017 10:38:49
%S 21,39,42,48,81,99,102,108,141,159,162,168,201,219,222,228,261,279,
%T 282,288,321,339,342,348,381,399,402,408,441,459,462,468,501,519,522,
%U 528,561,579,582,588,621,639,642,648,681,699,702,708,741,759,762,768,801
%N Last digit of F(n) is 6 where F(n) is the n-th Fibonacci number.
%C Sequence contains numbers of form (21+60k), (39+60k), (42+60k), (48+60k), with k>=0.
%H Colin Barker, <a href="/A072708/b072708.txt">Table of n, a(n) for n = 1..1000</a>
%H <a href="/index/Rec#order_05">Index entries for linear recurrences with constant coefficients</a>, signature (1,0,0,1,-1).
%F G.f.: x*(12*x^4+6*x^3+3*x^2+18*x+21) / (x^5-x^4-x+1). - _Colin Barker_, Jun 16 2013
%F a(n) = (-3/4+(3*i)/4)*((1+i)*(-1)^n + (5+2*i)*(-i)^n + (2+5*i)*i^n - (10+10*i)*n) where i=sqrt(-1). - _Colin Barker_, Oct 16 2015
%t LinearRecurrence[{1,0,0,1,-1},{21,39,42,48,81},60] (* _Harvey P. Dale_, Aug 28 2017 *)
%o (PARI) a(n) = (-3/4+(3*I)/4)*((1+I)*(-1)^n + (5+2*I)*(-I)^n + (2+5*I)*I^n - (10+10*I)*n) \\ _Colin Barker_, Oct 16 2015
%o (PARI) Vec(x*(12*x^4+6*x^3+3*x^2+18*x+21)/(x^5-x^4-x+1) + O(x^100)) \\ _Colin Barker_, Oct 16 2015
%Y Cf. A000045, A003893.
%K nonn,base,easy
%O 1,1
%A _Benoit Cloitre_, Aug 07 2002
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