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

1,3

Links

Table of n, a(n) for n=1..22.

Formula

a(n) = A004647(n-1)^3.

Example

64 is in the sequence because it is a perfect cube (64 = 4^3) whose digits appear in nonincreasing order.

Mathematica

Select[Range[0, 4*10^6]^3, Max@ Differences[IntegerDigits[#]] <= 0 &] (* Amiram Eldar, Mar 30 2022 *)

Prog

(PARI) ok(n) = digits(n) == vecsort(digits(n), , 4) && ispower(n, 3)

Crossrefs

Cf. A004647, A028820, A028864, A234848, A273045.

Intersection of A000578 and A009996.

Sequence in context: A293144 A349266 A111984 * A278145 A287230 A378421

Adjacent sequences: A352718 A352719 A352720 * A352722 A352723 A352724

Keyword

nonn,base

Author

Antonio Roldán, Mar 30 2022

Status

approved