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 A247127 #10 Feb 06 2017 18:55:30 %S A247127 1,0,0,1,4,0,9,8,24,17,78,64,227,212,664,699,2004,2220,6033,7196, %T A247127 18112,22859,54882,72560,166251,229284,505632,721421,1540532,2264668, %U A247127 4702135,7092742,14376450,22165709,44024116,69154334,134973515,215459398,414268932 %N A247127 Number of tilings of a 5 X n rectangle using n pentominoes of shapes V, U, X, N. %H A247127 Alois P. Heinz, <a href="/A247127/b247127.txt">Table of n, a(n) for n = 0..1000</a> %H A247127 Wikipedia, <a href="https://en.wikipedia.org/wiki/Pentomino">Pentomino</a> %F A247127 G.f.: see Maple program. %p A247127 gf:= -(4*x^18 +4*x^17 -8*x^16 -3*x^15 -9*x^14 +2*x^13 -3*x^12 +5*x^11 -7*x^10 +x^9 -7*x^8 -x^6 -2*x^5 -x^3+1) / (32*x^26 +32*x^25 -32*x^24 +8*x^23 -120*x^22 +12*x^21 -124*x^20 +36*x^19 -123*x^18 +35*x^17 -106*x^16 +20*x^15 -62*x^14 -23*x^13 -22*x^12 -36*x^11 +5*x^10 -18*x^9 +13*x^8 -4*x^7 +8*x^6 +2*x^5 +4*x^4 +2*x^3-1): %p A247127 a:= n-> coeff(series(gf, x, n+1), x, n): %p A247127 seq(a(n), n=0..50); %Y A247127 Cf. A174249, A233427, A247126. %K A247127 nonn %O A247127 0,5 %A A247127 _Alois P. Heinz_, Nov 19 2014