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 A141397 #16 Jul 07 2024 17:44:17
%S A141397 1,5,19,62,193,587,1771,5324,15985,47969,143923,431786,1295377,
%T A141397 3886151,11658475,34975448,104926369,314779133,944337427,2833012310,
%U A141397 8499036961,25497110915,76491332779,229473998372,688421995153,2065265985497,6195797956531,18587393869634
%N A141397 a(n) = 3*a(n-1) + A001651(n+1).
%C A141397 Row sums of triangle A141396.
%H A141397 <a href="/index/Rec#order_04">Index entries for linear recurrences with constant coefficients</a>, signature (4,-2,-4,3)
%F A141397 G.f.: ( -1-x-x^2 ) / ( (1+x)*(3*x-1)*(x-1)^2 ). a(n) = (-1)^n/16 -3*n/4 -3/2 +13*3^(n+1)/16. - _R. J. Mathar_, Feb 16 2011
%e A141397 a(2) = 19 = 3*a(1) + A001651(3) = 3*5 + 4 where A001651(3) = 4.
%e A141397 a(2) = 19 = sum of row 2 terms of triangle A141396: (4 + 6 + 9).
%t A141397 LinearRecurrence[{4,-2,-4,3},{1,5,19,62},50] (* _Harvey P. Dale_, Jul 07 2024 *)
%o A141397 (PARI) Vec((-1-x-x^2) / ((1+x)*(3*x-1)*(x-1)^2) + O(x^40)) \\ _Michel Marcus_, Jan 21 2015
%Y A141397 Cf. A141396, A001651.
%K A141397 nonn,easy
%O A141397 0,2
%A A141397 _Gary W. Adamson_, Jun 29 2008