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a(n) = 8*n + 4 + n mod 2.
2

%I #14 Sep 08 2022 08:45:50

%S 4,13,20,29,36,45,52,61,68,77,84,93,100,109,116,125,132,141,148,157,

%T 164,173,180,189,196,205,212,221,228,237,244,253,260,269,276,285,292,

%U 301,308,317,324,333,340,349,356,365,372,381,388,397,404,413,420,429,436

%N a(n) = 8*n + 4 + n mod 2.

%C First differences of A173511;

%C a(n+1) - a(n) = A010729(n+1).

%H <a href="/index/Rec#order_03">Index entries for linear recurrences with constant coefficients</a>, signature (1, 1, -1).

%F G.f.: (4 + 9*x + 3*x^2)/((1 + x)*(1 - x)^2). - _Philippe Deléham_, Nov 29 2016

%t LinearRecurrence[{1, 1, -1}, {4, 13, 20}, 60] (* _Vincenzo Librandi_, Nov 29 2016 *)

%o (Magma) [8*n+4+n mod 2: n in [0..60]]; // _Vincenzo Librandi_, Nov 29 2016

%K nonn

%O 0,1

%A _Reinhard Zumkeller_, Feb 20 2010