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 A057649 #6 Jun 22 2022 19:58:05 %S A057649 1,1,1,2,3,6,12,27,63,155,402,1087,3068,8996,27340,85905,278485, %T A057649 929713,3191201,11245603,40631628,150342633,569071745,2201355134, %U A057649 8694775795,35035655103,143916920872,602218550964,2565370007349,11118142868084,48994958103507 %N A057649 Nearest integer to ratio of volume of n-dimensional cube of side 2 to volume of n-dimensional ball of radius 1. %D A057649 J. H. Conway and N. J. A. Sloane, "Sphere Packings, Lattices and Groups", Springer-Verlag, p. 9. %F A057649 a(n) = 2^n*GAMMA(n/2+1)/Pi^(n/2). %Y A057649 Cf. A072168, A072345, A072346. %K A057649 nonn %O A057649 0,4 %A A057649 _N. J. A. Sloane_, Sep 06 2003