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a(n) = 22*n + 1.
11

%I #21 Sep 08 2022 08:45:45

%S 1,23,45,67,89,111,133,155,177,199,221,243,265,287,309,331,353,375,

%T 397,419,441,463,485,507,529,551,573,595,617,639,661,683,705,727,749,

%U 771,793,815,837,859,881,903,925,947,969,991,1013,1035,1057,1079,1101,1123

%N a(n) = 22*n + 1.

%D Italo Ghersi, Matematica dilettevole e curiosa, p. 139, Hoepli, Milano, 1967. [From _Vincenzo Librandi_, Dec 02 2009]

%H G. C. Greubel, <a href="/A161709/b161709.txt">Table of n, a(n) for n = 0..1000</a>

%H <a href="/index/Rec#order_02">Index entries for linear recurrences with constant coefficients</a>, signature (2,-1).

%F From _G. C. Greubel_, Sep 18 2019: (Start)

%F a(n) = 2*a(n-1) - a(n-2).

%F G.f.: (1 + 21*x)/(1-x)^2.

%F E.g.f.: (1 + 22*x)*exp(x). (End)

%p seq(1+22*n, n=0..60); # _G. C. Greubel_, Sep 18 2019

%t 22*Range[0,60]+1 (* _Harvey P. Dale_, Jan 09 2011 *)

%o (PARI) vector(60, n, 22*n-21) \\ _G. C. Greubel_, Sep 18 2019

%o (Magma) [1+22*n: n in [0..60]]; // _G. C. Greubel_, Sep 18 2019

%o (Sage) [1+22*n for n in (0..60)] # _G. C. Greubel_, Sep 18 2019

%o (GAP) List([0..60], n-> 1+22*n ); # _G. C. Greubel_, Sep 18 2019

%Y Cf. A005408, A008604, A016813, A016921, A017281, A017533, A128470, A158057, A161700, A161705, A161714.

%K nonn,easy

%O 0,2

%A _Reinhard Zumkeller_, Jun 17 2009