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%I #14 Sep 08 2022 08:46:20
%S 1,7,14,23,36,57,94,163,296,557,1074,2103,4156,8257,16454,32843,65616,
%T 131157,262234,524383,1048676,2097257,4194414,8388723,16777336,
%U 33554557,67108994,134217863,268435596,536871057,1073741974,2147483803,4294967456,8589934757
%N a(n) = 5*n + 2^n.
%C Also the number of chordless cycles in 2n-crossed prism graph for n >= 3.
%H Vincenzo Librandi, <a href="/A297663/b297663.txt">Table of n, a(n) for n = 0..1000</a>
%H Eric Weisstein's World of Mathematics, <a href="http://mathworld.wolfram.com/ChordlessCycle.html">Chordless Cycle</a>
%H Eric Weisstein's World of Mathematics, <a href="http://mathworld.wolfram.com/CrossedPrismGraph.html">Crossed Prism Graph</a>
%H <a href="/index/Rec#order_03">Index entries for linear recurrences with constant coefficients</a>, signature (4,-5,2)
%F a(n) = 4*a(n-1) - 5*a(n-2) + 2*a(n-3).
%F G.f.: (-1 - 3*x + 9*x^2)/((-1 + x)^2*(-1 + 2*x)).
%t Table[5 n + 2^n, {n, 0, 20}]
%t LinearRecurrence[{4, -5, 2}, {7, 14, 23}, {0, 20}]
%t seq = CoefficientList[Series[(-1 - 3 x + 9 x^2)/((-1 + x)^2 (-1 + 2 x)), {x, 0, 20}], x]
%o (Magma) I:=[1,7,14]; [n le 3 select I[n] else 4*Self(n-1)- 5*Self(n-2)+2*Self(n-3): n in [1..40]]; // _Vincenzo Librandi_, Feb 21 2018
%K nonn,easy
%O 0,2
%A _Eric W. Weisstein_, Jan 02 2018
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