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a(n) = A027082(n, n+2)
2

%I #22 Sep 16 2024 12:07:35

%S 2,6,14,28,54,102,190,352,650,1198,2206,4060,7470,13742,25278,46496,

%T 85522,157302,289326,532156,978790,1800278,3311230,6090304,11201818,

%U 20603358,37895486,69700668,128199518,235795678,433695870

%N a(n) = A027082(n, n+2)

%H Paolo Xausa, <a href="/A027083/b027083.txt">Table of n, a(n) for n = 2..1000</a>

%H <a href="/index/Rec#order_04">Index entries for linear recurrences with constant coefficients</a>, signature (2,0,0,-1).

%F G.f.: (2x^2(1+x+x^2))/((1-x)(1-x-x^2-x^3)). Cf. A008937.

%F a(n) = A027024(n) + 1.

%F a(n) = A000213(n+3) -3. - _R. J. Mathar_, Jun 24 2020

%t LinearRecurrence[{2, 0, 0, -1}, {2, 6, 14, 28}, 50] (* _Paolo Xausa_, Sep 16 2024 *)

%Y Cf. A008937, A027024, A027082.

%K nonn,easy

%O 2,1

%A _Clark Kimberling_