Year-end appeal: Please make a donation to the OEIS Foundation to support ongoing development and maintenance of the OEIS. We are now in our 61st year, we have over 378,000 sequences, and we’ve reached 11,000 citations (which often say “discovered thanks to the OEIS”).
%I #13 Jul 27 2021 10:20:54
%S 1,11,2,22,3,33,4,44,5,55,6,66,7,77,8,88,9,99,10,110,11,121,12,132,13,
%T 143,14,154,15,165,16,176,17,187,18,198,19,209,20,220,21,231,22,242,
%U 23,253,24,264,25,275,26,286,27,297,28,308,29,319,30,330,31,341,32,352
%N List of pairs n,11*n
%H <a href="/index/Rec#order_04">Index entries for linear recurrences with constant coefficients</a>, signature (0, 2, 0, -1).
%F a(n)=(1/4)*(12*n+10*n*(-1)^n+1+(-1)^(n-1)) for n > 1, with a(1) = 1 (corrected by _Jon E. Schoenfield_, Jun 19 2010)
%F G.f.: (1+11 x)/(-1+x^2)^2 (* _Harvey P. Dale_, Jul 27 2021 *)
%t Flatten[Table[{n,11n},{n,40}]] (* or *) LinearRecurrence[{0,2,0,-1},{1,11,2,22},80] (* _Harvey P. Dale_, Nov 25 2015 *)
%K nonn,tabf
%O 1,2
%A _Vincenzo Librandi_, Apr 23 2010
%E Partially edited by _N. J. A. Sloane_, Jun 23 2010