This is a front-end for the Online Encyclopedia of Integer Sequences, made by Christian Perfect. The idea is to provide OEIS entries in non-ancient HTML, and then to think about how they're presented visually. The source code is on GitHub.
%I A164826 #21 Apr 08 2024 12:28:37
%S A164826 2,1,12,13,142,155,1692,1847,20162,22009,240252,262261,2862862,
%T A164826 3125123,34114092,37239215,406506242,443745457,4843960812,5287706269,
%U A164826 57721023502,63008729771,687808321212,750817050983,8195978831042
%N A164826 Sequences A087800 and A077416 interleaved.
%H A164826 <a href="/index/Rec#order_04">Index entries for linear recurrences with constant coefficients</a>, signature (0,12,0,-1).
%F A164826 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 A164826 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 A164826 LinearRecurrence[{0,12,0,-1},{2,1,12,13},30] (* _Harvey P. Dale_, Oct 02 2017 *)
%Y A164826 Cf. A087800, A077416, A000032, A162671.
%K A164826 nonn,easy,less
%O A164826 1,1
%A A164826 _Mark Dols_, Aug 27 2009
%E A164826 Better name by _Paul Muljadi_, Jan 13 2011