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 A001509 #35 Sep 07 2025 16:15:53
%S A001509 6,336,1716,4896,10626,19656,32736,50616,74046,103776,140556,185136,
%T A001509 238266,300696,373176,456456,551286,658416,778596,912576,1061106,
%U A001509 1224936,1404816,1601496,1815726,2048256,2299836,2571216,2863146,3176376,3511656,3869736,4251366
%N A001509 a(n) = (5*n + 1)*(5*n + 2)*(5*n + 3).
%H A001509 T. D. Noe, <a href="/A001509/b001509.txt">Table of n, a(n) for n = 0..1000</a>
%H A001509 <a href="/index/Rec#order_04">Index entries for linear recurrences with constant coefficients</a>, signature (4,-6,4,-1).
%F A001509 a(n) = A016861(n) * A016873(n) * A016885(n). - _Wesley Ivan Hurt_, May 07 2014
%F A001509 G.f.: 6*(1 + 52*x + 68*x^2 + 4*x^3)/(1 - x)^4. - _Stefano Spezia_, Jan 03 2023
%F A001509 Sum_{n>=0} 1/a(n) = sqrt(2*(25-11*sqrt(5))/5)*Pi/20 + log(phi)/(2*sqrt(5)), where phi is the golden ratio (A001622). - _Amiram Eldar_, Jan 26 2023
%F A001509 From _Elmo R. Oliveira_, Sep 07 2025: (Start)
%F A001509 E.g.f.: exp(x)*(6 + 330*x + 525*x^2 + 125*x^3).
%F A001509 a(n) = 4*a(n-1) - 6*a(n-2) + 4*a(n-3) - a(n-4). (End)
%p A001509 A001509:=n->(5*n+1)*(5*n+2)*(5*n+3); seq(A001509(n), n=0..50); # _Wesley Ivan Hurt_, May 07 2014
%t A001509 Table[(5*n + 1)*(5*n + 2)*(5*n + 3), {n, 0, 100}] (* _Harvey P. Dale_, Apr 21 2011 *)
%Y A001509 Cf. A001622, A016861, A016873, A016885.
%K A001509 nonn,easy,changed
%O A001509 0,1
%A A001509 _N. J. A. Sloane_, Dec 11 1996