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 A179539 #9 Mar 31 2025 12:04:22 %S A179539 1,0,4,24,224,2480,32448,488992,8343040,158976576,3346392320, %T A179539 77118115712,1931148192768,52214924020480,1516090021970944, %U A179539 47049148379742720,1554087628854837248,54438650425975718912,2015738569973900021760,78666734375195278145536,3227298917806767126691840 %N A179539 a(0) = 1, a(1) = 0, a(n) = 2*n*(a(n-1) + a(n-2)), n > 1. %F A179539 D-finite with recurrence: 2*n*a(n-2) + 2*n*a(n - 1) - a(n) = 0. _Georg Fischer_, Mar 31 2025 %e A179539 a(2)= 4*(0+1)=4, a(3)=6*(4+0)=24, a(4)=8*(24+4)=224... %Y A179539 Cf. A055596. %K A179539 nonn,easy %O A179539 0,3 %A A179539 _Gary Detlefs_, Jul 18 2010 %E A179539 Definition corrected by _Bruno Berselli_, Jul 20 2010 %E A179539 Typo in a(7) corrected by _Georg Fischer_, Mar 31 2025