%I #21 Apr 08 2024 12:28:37

%S 2,1,12,13,142,155,1692,1847,20162,22009,240252,262261,2862862,

%T 3125123,34114092,37239215,406506242,443745457,4843960812,5287706269,

%U 57721023502,63008729771,687808321212,750817050983,8195978831042

%N Sequences A087800 and A077416 interleaved.

%H <a href="/index/Rec#order_04">Index entries for linear recurrences with constant coefficients</a>, signature (0,12,0,-1).

%F a(n) = a(n-1)+a(n-2) for n even, a(n) = 10*a(n-1)+a(n-2) for n odd; with a(1) = 2, a(2) = 1.

%F a(n) = 12*a(n-2)-a(n-4). G.f.: x*(x^3-12*x^2+x+2) / (x^4-12*x^2+1). [_Colin Barker_, Feb 18 2013]

%t LinearRecurrence[{0,12,0,-1},{2,1,12,13},30] (* _Harvey P. Dale_, Oct 02 2017 *)

%Y Cf. A087800, A077416, A000032, A162671.

%K nonn,easy,less

%O 1,1

%A _Mark Dols_, Aug 27 2009

%E Better name by _Paul Muljadi_, Jan 13 2011