login
The OEIS is supported by the many generous donors to the OEIS Foundation.

 

Logo
Hints
(Greetings from The On-Line Encyclopedia of Integer Sequences!)
A168486 Numbers that are congruent to {2, 5} mod 11. 1
2, 5, 13, 16, 24, 27, 35, 38, 46, 49, 57, 60, 68, 71, 79, 82, 90, 93, 101, 104, 112, 115, 123, 126, 134, 137, 145, 148, 156, 159, 167, 170, 178, 181, 189, 192, 200, 203, 211, 214, 222, 225, 233, 236, 244, 247, 255, 258, 266, 269, 277, 280, 288, 291, 299, 302, 310 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,1

LINKS

David Lovler, Table of n, a(n) for n = 1..10000 (first 1000 terms from Vincenzo Librandi)

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

FORMULA

a(n) = 11*n - a(n-1) - 4 with n>1, a(1)=2.

From R. J. Mathar, Mar 21 2010, Jul 07 2015: (Start)

a(n) = (22*n - 5*(-1)^n - 19)/4.

a(n) = a(n-1) + a(n-2) - a(n-3).

G.f.: x*(2 + 3*x + 6*x^2)/ ((1+x) * (x-1)^2). (End)

E.g.f.: (1/2)*(12 + (11*x - 12)*cosh(x) + (11*x - 7)*sinh(x)). - G. C. Greubel, Jul 23 2016

E.g.f.: (12 + (11*x -12)*exp(x) + 5*sinh(x))/2. - David Lovler, Jul 16 2022

MATHEMATICA

Select[Range[310], MemberQ[{2, 5}, Mod[#, 11]]&] (* Ray Chandler, Jul 07 2015 *)

LinearRecurrence[{1, 1, -1}, {2, 5, 13}, 57] (* Ray Chandler, Jul 07 2015 *)

Rest[CoefficientList[Series[x*(2+3*x+6*x^2)/((1+x)*(x-1)^2), {x, 0, 57}], x] ] (* Ray Chandler, Jul 07 2015 *)

PROG

(PARI) a(n) = (22*n - 5*(-1)^n - 19)/4 \\ David Lovler, Jul 16 2022

CROSSREFS

Sequence in context: A049476 A216889 A334494 * A038914 A019419 A175256

Adjacent sequences: A168483 A168484 A168485 * A168487 A168488 A168489

KEYWORD

nonn,easy

AUTHOR

Vincenzo Librandi, Nov 27 2009

EXTENSIONS

Leading 2 added by R. J. Mathar, Jul 07 2015

STATUS

approved

Lookup | Welcome | Wiki | Register | Music | Plot 2 | Demos | Index | Browse | More | WebCam
Contribute new seq. or comment | Format | Style Sheet | Transforms | Superseeker | Recents
The OEIS Community | Maintained by The OEIS Foundation Inc.

License Agreements, Terms of Use, Privacy Policy. .

Last modified March 5 05:59 EST 2023. Contains 360897 sequences. (Running on oeis4.)