This is a front-end for the Online Encyclopedia of Integer Sequences, made by Christian Perfect. The idea is to provide OEIS entries in non-ancient HTML, and then to think about how they're presented visually. The source code is on GitHub.
%I A139611 #23 May 05 2024 18:04:53
%S A139611 11,66,121,176,231,286,341,396,451,506,561,616,671,726,781,836,891,
%T A139611 946,1001,1056,1111,1166,1221,1276,1331,1386,1441,1496,1551,1606,1661,
%U A139611 1716,1771,1826,1881,1936,1991,2046,2101,2156,2211,2266
%N A139611 a(n) = 55*n + 11.
%C A139611 Numbers of the 11th column of positive numbers in the square array of nonnegative and polygonal numbers A139600.
%H A139611 Vincenzo Librandi, <a href="/A139611/b139611.txt">Table of n, a(n) for n = 0..5000</a>
%H A139611 <a href="/index/Pol#polygonal_numbers">Index to sequences related to polygonal numbers</a>
%H A139611 <a href="/index/Rec#order_02">Index entries for linear recurrences with constant coefficients</a>, signature (2,-1).
%F A139611 a(n) = A057145(n+2,11).
%F A139611 a(n) = 11 * A016861(n). - _Wesley Ivan Hurt_, Apr 16 2014
%F A139611 G.f.: 11*(1+4*x)/(x-1)^2 . - _R. J. Mathar_, Jul 28 2016
%F A139611 From _Elmo R. Oliveira_, Apr 16 2024: (Start)
%F A139611 E.g.f.: 11*exp(x)*(1 + 5*x).
%F A139611 a(n) = 11*(A000566(n+1) - A000566(n)).
%F A139611 a(n) = 2*a(n-1) - a(n-2) for n >= 2. (End)
%p A139611 A139611:=n->55*n + 11; seq(A139611(n), n=0..50); # _Wesley Ivan Hurt_, Apr 16 2014
%t A139611 Table[55 n + 11, {n, 0, 50}] (* _Wesley Ivan Hurt_, Apr 16 2014 *)
%o A139611 (Magma) [11*(5*n + 1): n in [0..60]]; // _Vincenzo Librandi_, Jul 23 2011
%o A139611 (PARI) a(n)=55*n+11 \\ _Charles R Greathouse IV_, Oct 05 2011
%Y A139611 Cf. A000566, A016861, A057145, A139600.
%K A139611 easy,nonn
%O A139611 0,1
%A A139611 _Omar E. Pol_, Apr 27 2008