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 A276506 #30 Jul 27 2021 11:29:08
%S A276506 1,9,90,981,11511,144108,1911771,26730981,392209380,6016681467,
%T A276506 96202473183,1599000785730,27563715220509,491777630207037,
%U A276506 9064781481234546,172346601006842337,3375007346801025099,67983454804021156548,1406921223577401454239,29881379179971835132761
%N A276506 E.g.f.: exp(9*(exp(x)-1)).
%C A276506 Number of ways of placing n labeled balls into n unlabeled (but 9-colored) boxes.
%H A276506 Alois P. Heinz, <a href="/A276506/b276506.txt">Table of n, a(n) for n = 0..514</a>
%F A276506 G.f.: A(x) satisfies 9*(x/(1-x))*A(x/(1-x)) = A(x)-1; nine times the binomial transform equals this sequence shifted one place left.
%p A276506 a:= proc(n) option remember; `if`(n=0, 1,
%p A276506 (1+add(binomial(n-1, k-1)*a(n-k), k=1..n-1))*9)
%p A276506 end:
%p A276506 seq(a(n), n=0..25); # _Alois P. Heinz_, Sep 25 2017
%t A276506 Table[BellB[n, 9], {n, 0, 30}]
%o A276506 (PARI) my(x='x+O('x^99)); Vec(serlaplace(exp(9*(exp(x)-1)))) \\ _Altug Alkan_, Sep 17 2016
%Y A276506 Cf. similar sequences with e.g.f. exp(k*(exp(x)-1)): A001861 (k=2), A027710 (k=3), A078944 (k=4), A144180 (k=5) A144223 (k=6), A144263 (k=7), A221159 (k=8), this sequence (k=9), A276507 (k=10).
%K A276506 nonn
%O A276506 0,2
%A A276506 _Vincenzo Librandi_, Sep 17 2016