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 A107584 #27 Sep 10 2024 16:11:18
%S A107584 1,0,8,52,240,1004,4072,16356,65504,262108,1048536,4194260,16777168,
%T A107584 67108812,268435400,1073741764,4294967232,17179869116,68719476664,
%U A107584 274877906868,1099511627696,4398046511020,17592186044328,70368744177572,281474976710560,1125899906842524
%N A107584 a(n) = 4^n - 4*n.
%C A107584 Numbers a(n) = k such that number m with n 4's and k 1's has digit product = digit sum = 4^n.
%H A107584 <a href="/index/Rec#order_03">Index entries for linear recurrences with constant coefficients</a>, signature (6,-9,4).
%F A107584 From _Harvey P. Dale_, Oct 21 2011: (Start)
%F A107584 a(n) = 6*a(n-1) - 9*a(n-2) + 4*a(n-3) with a(0)=1, a(1)=0, and a(2)=8.
%F A107584 G.f.: (-17*x^2+6*x-1)/((x-1)^2*(4*x-1)). (End)
%F A107584 E.g.f.: exp(x)*(exp(3*x) - 4*x). - _Elmo R. Oliveira_, Sep 10 2024
%e A107584 Corresponding numbers m are 1, 4, 1111111144, ...
%t A107584 Table[4^m-4*m, {m, 0, 20}]
%t A107584 LinearRecurrence[{6,-9,4},{1,0,8},30] (* _Harvey P. Dale_, Oct 21 2011 *)
%o A107584 (Magma) [(4^n - 4*n): n in [0..25]]; // _Vincenzo Librandi_, Dec 16 2010
%o A107584 (PARI) a(n)=4^n-4*n \\ _Charles R Greathouse IV_, Sep 08 2012
%o A107584 (Python)
%o A107584 def A107584(n): return (1<<(n<<1))-(n<<2) # _Chai Wah Wu_, Nov 29 2023
%Y A107584 Cf. A107583, A107585.
%K A107584 nonn,easy
%O A107584 0,3
%A A107584 _Zak Seidov_, May 16 2005
%E A107584 More terms from _Vincenzo Librandi_, Dec 16 2010
%E A107584 Corrected by _Charles R Greathouse IV_, Sep 08 2012