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 A298424 #6 Jan 19 2018 02:21:22 %S A298424 1,2,3,4,5,8,11,14,16,31,32,49,64,76,86,127,128,256,301,424,454,512, %T A298424 709,722,886,1024,1532,1589,1849,2048,2096,3101,3986,4096,5381,6418, %U A298424 6859,8192,9761,9952,11236,13766,13951,14554,16384,19049,21884,22463,23512 %N A298424 Matula-Goebel numbers of rooted trees in which all positive outdegrees are the same. %e A298424 Sequence of trees begins: %e A298424 1 o %e A298424 2 (o) %e A298424 3 ((o)) %e A298424 4 (oo) %e A298424 5 (((o))) %e A298424 8 (ooo) %e A298424 11 ((((o)))) %e A298424 14 (o(oo)) %e A298424 16 (oooo) %e A298424 31 (((((o))))) %e A298424 32 (ooooo) %e A298424 49 ((oo)(oo)) %e A298424 64 (oooooo) %e A298424 76 (oo(ooo)) %e A298424 86 (o(o(oo))) %e A298424 127 ((((((o)))))) %e A298424 128 (ooooooo) %e A298424 256 (oooooooo) %e A298424 301 ((oo)(o(oo))) %e A298424 424 (ooo(oooo)) %e A298424 454 (o((oo)(oo))) %e A298424 512 (ooooooooo) %e A298424 709 (((((((o))))))) %e A298424 722 (o(ooo)(ooo)) %e A298424 886 (o(o(o(oo)))) %t A298424 MGtree[n_]:=If[n===1,{},MGtree/@Flatten[Cases[FactorInteger[n],{p_,k_}:>Table[PrimePi[p],{k}]]]]; %t A298424 soQ[n_]:=Or[n===1,SameQ@@Length/@Cases[MGtree[n],{__},{0,Infinity}]]; %t A298424 Select[Range[1000],soQ] %Y A298424 Cf. A000081, A000598, A001190, A003238, A007097, A111299, A214577, A276625, A298422, A298423, A298426. %K A298424 nonn %O A298424 1,2 %A A298424 _Gus Wiseman_, Jan 19 2018