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 A352182 #13 Apr 22 2024 13:34:39 %S A352182 0,30,2970,291060,28520940,2794761090,273858065910,26835295698120, %T A352182 2629585120349880,257672506498590150,25249276051741484850, %U A352182 2474171380564166925180,242443546019236617182820,23756993338504624316991210,2327942903627433946447955790,228114647562150022127582676240 %N A352182 Twice A200994. %C A352182 Also 3 times A200993 and 6 times A352181. %C A352182 Numbers that both doubles and triples of triangular numbers. %H A352182 Editors, L'Intermédiaire des Mathématiciens, <a href="/A072256/a072256.pdf">Query 4500: The equation x(x+1)/2 = y*(y+1)/3</a>, L'Intermédiaire des Mathématiciens, 22 (1915), 255-260 (I). %H A352182 Editors, L'Intermédiaire des Mathématiciens, <a href="/A072256/a072256_1.pdf">Query 4500: The equation x(x+1)/2 = y*(y+1)/3</a>, L'Intermédiaire des Mathématiciens, 22 (1915), 255-260 (II). %H A352182 Editors, L'Intermédiaire des Mathématiciens, <a href="/A072256/a072256_2.pdf">Query 4500: The equation x(x+1)/2 = y*(y+1)/3</a>, L'Intermédiaire des Mathématiciens, 22 (1915), 255-260 (III). %H A352182 Editors, L'Intermédiaire des Mathématiciens, <a href="/A072256/a072256_3.pdf">Query 4500: The equation x(x+1)/2 = y*(y+1)/3</a>, L'Intermédiaire des Mathématiciens, 22 (1915), 255-260 (IV). %H A352182 <a href="/index/Rec#order_03">Index entries for linear recurrences with constant coefficients</a>, signature (99,-99,1). %F A352182 From _Chai Wah Wu_, Apr 22 2024: (Start) %F A352182 a(n) = 99*a(n-1) - 99*a(n-2) + a(n-3) for n > 2. %F A352182 G.f.: -30*x/((x - 1)*(x^2 - 98*x + 1)). (End) %F A352182 a(n) = 30*A278620. - _Hugo Pfoertner_, Apr 22 2024 %Y A352182 Cf. A200993, A200994, A278620, A352181. %K A352182 nonn,easy %O A352182 0,2 %A A352182 _N. J. A. Sloane_, Mar 08 2022