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 A323121 #6 Jan 07 2019 15:54:54 %S A323121 0,0,2,3,12,23,61,132,294,639,1377,2922,6178,12953,27021,56106,116030, %T A323121 239090,491202,1006361,2056755,4194230,8536023,17340787,35168957, %U A323121 71217347,144012394,290835635,586637532,1181960546,2378920014,4783326807,9609050910,19286596636 %N A323121 Number of compositions of n where the difference between largest and smallest parts equals four. %H A323121 Alois P. Heinz, <a href="/A323121/b323121.txt">Table of n, a(n) for n = 4..3407</a> %F A323121 a(n) ~ c * d^n, where d = 1.9659482366454853371899373759344013961513... is the real root of the equation d^5 - d^4 - d^3 - d^2 - d - 1 = 0 or d^6 - 2*d^5 + 1 = 0 and c = 0.53792611681915978492363258130015596032604545873525287924... is the real root of the equation 9584*c^5 - 9584*c^4 + 3160*c^3 - 480*c^2 + 35*c - 1 = 0. - _Vaclav Kotesovec_, Jan 07 2019 %Y A323121 Column k=4 of A214258. %K A323121 nonn %O A323121 4,3 %A A323121 _Alois P. Heinz_, Jan 05 2019