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 A001526 #32 Oct 25 2024 07:44:48
%S A001526 6,104,300,594,986,1476,2064,2750,3534,4416,5396,6474,7650,8924,10296,
%T A001526 11766,13334,15000,16764,18626,20586,22644,24800,27054,29406,31856,
%U A001526 34404,37050,39794,42636,45576,48614,51750,54984,58316,61746,65274,68900,72624,76446
%N A001526 a(n) = (7*n+1)*(7*n+6).
%H A001526 T. D. Noe, <a href="/A001526/b001526.txt">Table of n, a(n) for n = 0..1000</a>
%H A001526 <a href="/index/Rec#order_03">Index entries for linear recurrences with constant coefficients</a>, signature (3,-3,1).
%F A001526 a(n) = 98*n + a(n-1) with a(0)=6. - _Vincenzo Librandi_, Nov 12 2010
%F A001526 From _Amiram Eldar_, Feb 19 2023: (Start)
%F A001526 a(n) = A016993(n)*A017053(n).
%F A001526 Sum_{n>=0} 1/a(n) = cot(Pi/7)*Pi/35 = 0.186388....
%F A001526 Product_{n>=0} (1 - 1/a(n)) = cosec(Pi/7)*cos(sqrt(29)*Pi/14).
%F A001526 Product_{n>=0} (1 + 1/a(n)) = cosec(Pi/7)*cos(sqrt(3/7)*Pi/2). (End)
%F A001526 G.f.: -2*(3+43*x+3*x^2)/(x-1)^3. - _R. J. Mathar_, Apr 23 2024
%F A001526 From _Elmo R. Oliveira_, Oct 25 2024: (Start)
%F A001526 E.g.f.: exp(x)*(6 + 49*x*(2 + x)).
%F A001526 a(n) = 3*a(n-1) - 3*a(n-2) + a(n-3) for n > 2. (End)
%t A001526 a[n_] := (7*n + 1)*(7*n + 6); Array[a, 40, 0] (* _Amiram Eldar_, Feb 19 2023 *)
%o A001526 (PARI) a(n)=(7*n+1)*(7*n+6) \\ _Charles R Greathouse IV_, Jun 17 2017
%Y A001526 Cf. A016993, A017053.
%K A001526 nonn,easy
%O A001526 0,1
%A A001526 _N. J. A. Sloane_