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 A257830 #9 May 11 2015 04:01:14
%S A257830 1,2,3,4,5,6,7,8,9,34,79,215,437,2514,3833,32453,35194,49672,5695449,
%T A257830 357129525,44683966971145538,383375167535817138,
%U A257830 4377829714163336859592836
%N A257830 The decimal representation of the geometric mean of the digits of n starts with the digits of n.
%C A257830 a(24) > 10^30.
%t A257830 pr[n_] := Union@Flatten@ Table[Union[ Times @@@ Flatten[Outer[Power, Subsets[ Range@9, {Length@e}], Permutations[e], 1], 1]], {e, IntegerPartitions@ n}]; sol[nd_] := Block[{p = ppr[nd], L}, L = Table[FromDigits[ RealDigits[x^(1/nd), 10, nd][[1]]], {x, p}]; L[[Select[Range@Length@p, Times @@ IntegerDigits[L[[#]]] == p[[#]] &]]]]; Union@ Flatten@ Array[sol, 17] (* terms with up to 17 digits *)
%o A257830 (PARI) is(n)=n==sqrtn(prod(i=1,#n=digits(n),n[i]),#n)\10^(1-#n) \\ _M. F. Hasler_, May 10 2015
%Y A257830 Cf. A257829, A007954, A004429, A004428.
%K A257830 base,nonn
%O A257830 1,2
%A A257830 _Giovanni Resta_, May 10 2015