来自在线整数百科全书的问候语!http://oeis.org/ Search: id:a054884 Showing 1-1 of 1 %I A054884 %S A054884 1,0,5,10,65,260,1365,6510,32865,162760,815365,4069010,20352865, %T A054884 101725260,508665365,2543131510,12715852865,63578287760,317892415365, %U A054884 1589457194010,7947290852865,39736429850260 %N A054884 Closed walks of length n along the edges of an icosahedron based at a vertex. %H A054884 Vincenzo Librandi,n,a(n)n=0…1000的表%F A054884 G.f.: -(1/12)/(5*t-1) + (5/12)/(t+1) - (1/2)/(5*t^2-1). %F A054884 a(n) = (5^n + (-1)^n*5 + 3*(1 + (-1)^n)*sqrt(5)^n)/12. %o A054884 (MAGMA) [Floor((5^n+(-1)^n*5+3*(1+(-1)^n)*Sqrt(5)^n)/12): n in [0..30]]; // _Vincenzo Librandi_, Aug 24 2011 %Y A054884 {a(n)/5} for n > 1 is A030517. %K A054884 nonn,walk %O A054884 0,3 %A A054884 Paolo Dominici (pl.dm(AT)libero.it), May 23 2000 # Content is available under The OEIS End-User License Agreement: http://oeis.org/LICENSE