Year-end appeal: Please make a donation to the OEIS Foundation to support ongoing development and maintenance of the OEIS. We are now in our 61st year, we have over 378,000 sequences, and we’ve reached 11,000 citations (which often say “discovered thanks to the OEIS”).
%I #10 Jul 02 2023 18:05:22
%S 1,4,17,73,311,1309,5447,22453,91871,373789,1514327,6115333,24636431,
%T 99073069,397878407,1596280213,6399436991,25640729149,102691925687,
%U 411154861093,1645781181551,6586610462029,26356900104167
%N a(n) = (3*4^n - 2*3^n + 2^n)/2.
%C Binomial transform of A053156.
%H <a href="/index/Rec#order_03">Index entries for linear recurrences with constant coefficients</a>, signature (9, -26, 24).
%F a(n) = (3*4^n - 2*3^n + 2^n)/2.
%F G.f.: (1-5x+7x^2)/(2(1-2x)(1-3x)(1-4x)).
%F E.g.f.: (3*exp(4x) - 2*exp(3x) + exp(2x))/2.
%t Table[(3 4^n-2 3^n+2^n)/2,{n,0,30}] (* _Harvey P. Dale_, Mar 14 2011 *)
%Y Cf. A083331.
%K easy,nonn
%O 0,2
%A _Paul Barry_, Apr 27 2003