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 A281389 #57 Jan 27 2017 13:19:23 %S A281389 2,9,8,625,7776,117649,128,6561,1000000000,25937424601,362797056, %T A281389 23298085122481,2541865828329,29192926025390625,32768, %U A281389 48661191875666868481,16926659444736,104127350297911241532841,10000000000000000000,278218429446951548637196401 %N A281389 Least k > 1 such that refactorable number k is an n-th power. %H A281389 S. Colton, <a href="https://cs.uwaterloo.ca/journals/JIS/colton/joisol.html">Refactorable Numbers - A Machine Invention</a>, J. Integer Sequences, Vol. 2, 1999. %H A281389 Joshua Zelinsky, <a href="https://cs.uwaterloo.ca/journals/JIS/VOL5/Zelinsky/zelinsky9.html">Tau Numbers: A Partial Proof of a Conjecture and Other Results </a>, Journal of Integer Sequences, Vol. 5 (2002), Article 02.2.8 %F A281389 a(n) = A281495(n)^n. %e A281389 a(4) = 625 because 625 = 5^4 is the least fourth power refactorable number that is greater than 1. %o A281389 (PARI) isA033950(n) = n % numdiv(n) == 0; %o A281389 a(n) = {my(k=2); while (!isA033950 (k^n), k++); k^n; } %Y A281389 Cf. A001597, A007947, A033950, A036907, A235524, A281495. %K A281389 nonn %O A281389 1,1 %A A281389 _Altug Alkan_, Jan 21 2017 %E A281389 More terms from _Giovanni Resta_, Jan 22 2017