A276697 Integers m such that A048390(m) is a cube.

0, 1, 2, 3, 4, 5, 6, 7, 8, 9, 1000, 1042, 2000, 3000, 4000, 5000, 6000, 7000, 8000, 9000, 321213, 642426, 1000000, 1042000, 2000000, 3000000, 4000000, 5000000, 6000000, 7000000, 8000000, 9000000, 10121026, 302102103, 321213000, 604204206, 642426000, 1000000000

Offset: 1

Author

Michel Marcus, Nov 06 2016

Keywords

• nonn
• base

Comments

Integers that become cubes when their digits d are replaced with d^3.

Sequence is infinite, since 10^(3*k) is a term for all k.

Examples

			For m <= 9, 1-digit integers, A048390(m) = m^3 so all integers <= 9 are terms of this sequence.
		

Crossrefs

Cf. A000578, A048386, A048390.

Programs

Magma

f:=func; [0] cat [k:k in [1..8000000]|IsPower(f(k),3)]; // Marius A. Burtea, Feb 13 2020

PARI

isok(n) = my(d = digits(n)); my(s = ""); for (k=1, #d, s = concat(s, Str(d[k]^3))); ispower(eval(s), 3);

Extensions

a(34)-a(38) from Jinyuan Wang, Feb 13 2020