来自在线整数百科全书的问候语!http://oeis.org/ Search: id:a000418 Showing 1-1 of 1 %I A000418 M4408 N1862 %S A000418 0,0,0,0,0,0,0,1,7,34,136,487,1615,5079,15349,45009,128899,362266, %T A000418 1002681,2740448,7411408,19865445,52840977,139624510,366803313, %U A000418 958696860,2494322662,6463281890,16686206047,42935345688,110142163940,281763465941 %N A000418 Number of n-node rooted trees of height 7. %D A000418 N. J. A. Sloane, A Handbook of Integer Sequences, Academic Press, 1973 (includes this sequence). %D A000418 N. J. A. Sloane and Simon Plouffe, The Encyclopedia of Integer Sequences, Academic Press, 1995 (includes this sequence). %H A000418 N. J. A. Sloane,n,a(n)n=1…200的表%H A000 0418 J. Riordan,树的高度和直径的枚举,IBM J.R.D. 4(1960),43-78.0%H A000 0418与有根树相关的序列的索引条目%H A000 0418与树相关的序列的索引条目%F A000 0418 A0348 24 A0348 23。- _Christian G. Bower_ %p A000418 For Maple program see link in A000235. %t A000418 b[n_, i_, k_] := b[n, i, k] = If[n == 0, 1, If[i < 1 || k < 1, 0, Sum[ Binomial[b[i - 1, i - 1, k - 1] + j - 1, j]*b[n - i*j, i - 1, k], {j, 0, n/i}]]]; a[n_] := b[n - 1, n - 1, 7] - b[n - 1, n - 1, 6]; Array[a, 40] (* _Jean-François Alcover_, Feb 08 2016, after _Alois P. Heinz_ in A034781 *) %Y A000418 Column h=7 of A034781. %K A000418 nonn %O A000418 1,9 %A A000418 _N. J. A. Sloane_ # Content is available under The OEIS End-User License Agreement: http://oeis.org/LICENSE