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 A367243 #7 Nov 12 2023 13:30:39
%S A367243 0,15,91,381,1375,4605,14791,46341,142975,436845,1326391,4010901,
%T A367243 12096175,36415485,109500391,329009061,988042975,2966160525,
%U A367243 8902544791,26715760821,80163535375,240523111965,721634347591,2165033066181,6495359245375,19486597829805,58460833676791
%N A367243 a(n) is the number of n-digit numbers whose difference between the largest and smallest digits is equal to 2.
%C A367243 a(n) is the number of n-digit numbers in A366959.
%H A367243 <a href="/index/Rec#order_03">Index entries for linear recurrences with constant coefficients</a>, signature (6,-11,6).
%F A367243 a(n) = (46*3^n - 93*2^n + 48)/6.
%F A367243 a(n) = 6*a(n-1) - 11*a(n-2) + 6*a(n-3) for n > 3.
%F A367243 O.g.f.: x^2*(15 + x)/((1 - x)*(1- 2*x)*(1 - 3*x)).
%F A367243 E.g.f.: (exp(x) - 1)^2*(46*exp(x) - 1)/6.
%t A367243 LinearRecurrence[{6,-11,6},{0,15,91},27]
%Y A367243 Cf. A366959.
%Y A367243 Cf. A000079, A000244.
%Y A367243 Cf. A367244, A367245, A367246, A367247, A367248, A367249, A367250.
%K A367243 nonn,base,easy
%O A367243 1,2
%A A367243 _Stefano Spezia_, Nov 11 2023