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 #15 Mar 12 2024 12:17:40
%S 1,2,5,10,23,46,105,210,479,958,2185,4370,9967,19934,45465,90930,
%T 207391,414782,946025,1892050,4315343,8630686,19684665,39369330,
%U 89792639,179585278,409593865,819187730,1868384047,3736768094,8522732505
%N a(n) = 5*a(n-2) - 2*a(n-4), n >= 4.
%C Floretion Algebra Multiplication Program, FAMP Code: 4kbaseksigcycsumseq[ - .25'i - .25i' + .25'ii' + .25'jj' + .25'kk' + .25'jk' + .25'kj' + .25e], sumtype: (Y[15], *, vesy)
%H <a href="/index/Rec#order_04">Index entries for linear recurrences with constant coefficients</a>, signature (0,5,0,-2).
%F a(2n) = A107839(n), a(2n+1) = A106709(n+1), a(n) - a(n-1) = A005824(n+2).
%F G.f.: (2*x+1)/(1-5*x^2+2*x^4).
%Y Cf. A107839, A106709, A005824, A054486.
%K easy,nonn
%O 0,2
%A _Creighton Dement_, Aug 18 2005