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 A385517 #5 Jul 02 2025 16:56:14 %S A385517 1,4,8,9,32,64,81,100,400,441,841,900,961,1000,6400,7744,7776,8000, %T A385517 8100,10000,40000,44100,64000,84100,90000,96100,100000,640000,774400, %U A385517 810000,1000000,3200000,4000000,4410000,8000000,8410000,8874441,9000000,9610000,9853321,10000000 %N A385517 Perfect powers whose digits are in nonincreasing order. %t A385517 perfectPowerQ[n_] :=n==1 || GCD @@ FactorInteger[n][[All, 2]] > 1; (* A001597 *) Select[Range[10^6], perfectPowerQ[#] && Max[Differences[IntegerDigits[#]]]<1 &] %Y A385517 Cf. A001597, A009995, A355060, A355062, A355063, A385516. %K A385517 nonn,base %O A385517 1,2 %A A385517 _Stefano Spezia_, Jul 01 2025