A253602 Numbers n such that the smallest exponent k for n and n^k to have common digits is 4.

22, 47, 92, 157, 187, 188, 192, 552, 558, 577, 707, 772, 922, 2522, 8338, 17177, 66888, 575757, 929522, 1717177, 8888588

Offset: 1

Author

Michel Marcus, Jan 05 2015

Keywords

• nonn
• base
• more

Examples

			22^2=484 and 22^3=10648 have no digits in common with 22, but 22^4=234256 has some, so 22 is in the sequence.
		

Crossrefs

Cf. A029790, A103173, A189056, A253600, A253601.

Programs

PARI

a253600(n) = {sd = Set(vecsort(digits(n))); k=2; while (#setintersect(sd, Set(vecsort(digits(n^k)))) == 0, k++); k;}
isok(n) = a253600(n) == 4;