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%I #20 Mar 17 2023 09:56:04
%S 3,8,6,16,12,32,24,64,48,128,96,256,192,512,384,1024,768,2048,1536,
%T 4096,3072,8192,6144,16384,12288,32768,24576,65536,49152,131072,98304,
%U 262144,196608,524288,393216,1048576,786432,2097152,1572864,4194304,3145728
%N a(n) = 2*a(n-2) for n > 2; a(1) = 3, a(2) = 8.
%C Interleaving of A007283 and A000079 without initial terms 1, 2, 4.
%C Binomial transform is A164303.
%H Vincenzo Librandi, <a href="/A164654/b164654.txt">Table of n, a(n) for n = 1..100</a>
%H <a href="/index/Rec#order_02">Index entries for linear recurrences with constant coefficients</a>, signature (0,2).
%F a(n) = (7+(-1)^n)*2^(1/4*(2*n-5+(-1)^n)).
%F G.f.: x*(3+8*x)/(1-2*x^2). - corrected by _Klaus Brockhaus_, Sep 18 2009
%t With[{lst2=2^Range[0,20]},Riffle[3*lst2,8*lst2]] (* or *) LinearRecurrence[ {0,2},{3,8},50](* _Harvey P. Dale_, Aug 20 2011 *)
%o (Magma) [ n le 2 select 5*n-2 else 2*Self(n-2): n in [1..41] ];
%o (Maxima) a[1]:3$ a[2]:8$ a[n]:=2*a[n-2]$ makelist(a[n], n, 1, 41); /* _Bruno Berselli_, May 23 2011
%o (PARI) a(n) = (7+(-1)^n)*2^((2*n-5+(-1)^n)/4) \\ _Charles R Greathouse IV_, Jun 11 2015
%Y Cf. A007283 (3*2^n), A000079 (powers of 2), A164303.
%K nonn,easy
%O 1,1
%A _Klaus Brockhaus_, Aug 20 2009
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