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 A303072 #18 Jun 10 2025 11:28:18
%S A303072 1,4,4,16,16,49,81,169,324,625,1296,2401,4900,9409,18769,36481,71824,
%T A303072 141376,276676,544644,1067089,2099601,4116841,8088336,15880225,
%U A303072 31181056,61230625,120209296,236083225,463497841,910168561,1787091076,3509140644,6890328064,13529411856
%N A303072 Number of minimal total dominating sets in the n-ladder graph.
%H A303072 Eric Weisstein's World of Mathematics, <a href="https://mathworld.wolfram.com/LadderGraph.html">Ladder Graph</a>.
%H A303072 Eric Weisstein's World of Mathematics, <a href="https://mathworld.wolfram.com/MinimalTotalDominatingSet.html">Minimal Total Dominating Set</a>.
%H A303072 <a href="/index/Rec#order_19">Index entries for linear recurrences with constant coefficients</a>, signature (-1,1,3,7,8,2,6,6,0,0,-6,-6,-2,-8,-7,-3,-1,1,1).
%F A303072 a(n) = A253412(n)^2.
%F A303072 G.f.: x*(-1 - 5*x - 7*x^2 - 13*x^3 - 9*x^4 - x^5 - 4*x^6 + 5*x^7 + 13*x^8 + 14*x^9 + 21*x^10 + 15*x^11 + 12*x^12 + 15*x^13 + 9*x^14 + 3*x^15 - 2*x^17 - x^18)/(-1 - x + x^2 + 3*x^3 + 7*x^4 + 8*x^5 + 2*x^6 + 6*x^7 + 6*x^8 - 6*x^11 - 6*x^12 - 2*x^13 - 8*x^14 - 7*x^15 - 3*x^16 - x^17 + x^18 + x^19).
%t A303072 Table[(RootSum[1 - #^2 - #^3 - #^4 + #^6 &, (9 - 18 #^2 + 23 #^3 - 3 #^4 + 32 #^5) #^n &]/229)^2, {n, 40}]
%t A303072 LinearRecurrence[{-1, 1, 3, 7, 8, 2, 6, 6, 0, 0, -6, -6, -2, -8, -7, -3, -1, 1, 1}, {1, 4, 4, 16, 16, 49, 81, 169,324, 625, 1296, 2401, 4900, 9409, 18769, 36481, 71824, 141376, 276676}, 40]
%t A303072 CoefficientList[Series[(-1 - 5 x - 7 x^2 - 13 x^3 - 9 x^4 - x^5 - 4 x^6 + 5 x^7 + 13 x^8 + 14 x^9 + 21 x^10 + 15 x^11 + 12 x^12 + 15 x^13 + 9 x^14 + 3 x^15 - 2 x^17 - x^18)/(-1 - x + x^2 + 3 x^3 + 7 x^4 + 8 x^5 + 2 x^6 + 6 x^7 + 6 x^8 - 6 x^11 - 6 x^12 - 2 x^13 - 8 x^14 - 7 x^15 - 3 x^16 - x^17 + x^18 + x^19), {x, 0, 40}], x]
%Y A303072 Row 2 of A303118.
%Y A303072 Cf. A290379, A302402, A303054.
%K A303072 nonn,easy
%O A303072 1,2
%A A303072 _Eric W. Weisstein_, Apr 18 2018