A352721 Perfect cubes whose decimal digits appear in nonincreasing order.
0, 1, 8, 64, 1000, 8000, 64000, 1000000, 8000000, 64000000, 1000000000, 8000000000, 64000000000, 1000000000000, 8000000000000, 64000000000000, 1000000000000000, 8000000000000000, 64000000000000000, 1000000000000000000, 8000000000000000000, 64000000000000000000
Offset: 1
Examples
64 is in the sequence because it is a perfect cube (64 = 4^3) whose digits appear in nonincreasing order.
Programs
-
Mathematica
Select[Range[0, 4*10^6]^3, Max@ Differences[IntegerDigits[#]] <= 0 &] (* Amiram Eldar, Mar 30 2022 *)
-
PARI
ok(n) = digits(n) == vecsort(digits(n),,4) && ispower(n,3)
Formula
a(n) = A004647(n-1)^3.