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A026042 a(n) = (d(n)-r(n))/5, where d = A026040 and r is the periodic sequence with fundamental period (4,0,4,3,4).

%I A026042 #9 Jun 13 2015 00:49:05
%S A026042 4,8,12,19,28,40,56,74,97,124,156,194,236,285,340,402,472,548,633,726,
%T A026042 828,940,1060,1191,1332,1484,1648,1822,2009,2208,2420,2646,2884,3137,
%U A026042 3404,3686,3984,4296,4625,4970,5332,5712,6108,6523,6956,7408,7880,8370,8881,9412,9964,10538,11132,11749
%N A026042 a(n) = (d(n)-r(n))/5, where d = A026040 and r is the periodic sequence with fundamental period (4,0,4,3,4).
%H A026042 <a href="/index/Rec#order_08">Index entries for linear recurrences with constant coefficients</a>, signature (3,-3,1,0,1,-3,3,-1).
%F A026042 a(n)=(n + 4)*(n^2 + 5*n + 18)/15 - 3/5 - (1/2 - 3/10*5^(1/2))/5*cos(2*n*Pi/5) + (1/10*(4*(5 + 5^(1/2))^(1/2) - (5 - 5^(1/2))^(1/2))*2^(1/2))/5*sin(2*n*Pi/5) - (3/10*5^(1/2) + 1/2)/5*cos(4*n*Pi/5) + (1/10*((5 + 5^(1/2))^(1/2) + 4*(5 - 5^(1/2))^(1/2))*2^(1/2))/5*sin(4*n*Pi/5) [From _Richard Choulet_, Dec 14 2008]
%F A026042 G.f. x*( 4-4*x+3*x^3-x^4-3*x^5+5*x^6-2*x^7 ) / ( (x^4+x^3+x^2+x+1)*(x-1)^4 ). - _R. J. Mathar_, Jun 22 2013
%Y A026042 A152856 [From _Richard Choulet_, Dec 14 2008]
%K A026042 nonn
%O A026042 1,1
%A A026042 _Clark Kimberling_