A168465 Numbers that are congruent to 2 or 7 mod 11.

2, 7, 13, 18, 24, 29, 35, 40, 46, 51, 57, 62, 68, 73, 79, 84, 90, 95, 101, 106, 112, 117, 123, 128, 134, 139, 145, 150, 156, 161, 167, 172, 178, 183, 189, 194, 200, 205, 211, 216, 222, 227, 233, 238, 244, 249, 255, 260, 266, 271, 277, 282, 288, 293, 299, 304, 310

Offset

1,1

Links

Vincenzo Librandi, Table of n, a(n) for n = 1..1000

Index entries for linear recurrences with constant coefficients, signature (1,1,-1).

Formula

G.f.: x*(4*x^2 + 5*x + 2) / ((x+1)*(x-1)^2).

a(n) = (22*n - (-1)^n - 3)/4 - 3. [Bruno Berselli, Jan 05 2013, modified Jul 08 2015]

E.g.f.: 4 + ((22*x - 15)*exp(x) - exp(-x))/4. - David Lovler, Sep 04 2022

Mathematica

Select[Range[310], MemberQ[{2, 7}, Mod[#, 11]]&] (* Ray Chandler, Jul 07 2015 *)
LinearRecurrence[{1, 1, -1}, {2, 7, 13}, 57] (* Ray Chandler, Jul 07 2015 *)
Rest[CoefficientList[Series[(4*x^2+5*x+2)*x/((x+1)*(x-1)^2), {x, 0, 57}], x]] (* Ray Chandler, Jul 07 2015 *)

Prog

(Magma) [(22*n-(-1)^n-3)/4-3: n in [1..60]]; // Bruno Berselli, Jul 08 2015
(PARI) a(n)=(22*n-(-1)^n-3)/4-3 \\ Charles R Greathouse IV, Jul 09 2015

Crossrefs

Sequence in context: A356107 A001966 A209886 * A140562 A155547 A007821

Adjacent sequences: A168462 A168463 A168464 * A168466 A168467 A168468

Keyword

nonn,easy

Author

Vincenzo Librandi, Nov 26 2009

Extensions

Definition corrected by Editors of the OEIS, Jul 07 2015

Status

approved