A253601 Numbers such that the smallest exponent for n and n^k to have common digits is 3.

4, 9, 17, 18, 24, 29, 33, 34, 38, 39, 44, 54, 57, 58, 59, 62, 67, 72, 79, 84, 88, 94, 144, 158, 173, 194, 209, 212, 224, 237, 238, 244, 247, 253, 257, 259, 307, 313, 314, 333, 334, 338, 349, 353, 359, 377, 388, 404, 409, 424, 437, 444, 447, 449, 454, 459, 467

Offset

1,1

Links

Iain Fox, Table of n, a(n) for n = 1..10000

Example

4^2=16 has no digits in common with 4, but 4^3=64 has some, so 4 is in the sequence.

Prog

(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) == 3;
(PARI) is(n) = my(d(k)=Set(digits(n^k))); !#setintersect(d(1), d(2)) && #setintersect(d(1), d(3)) \\ Iain Fox, Aug 07 2018

Crossrefs

Cf. A103173, A189056, A253600, A253602.

Sequence in context: A110979 A073173 A313352 * A313353 A341789 A313354

Adjacent sequences: A253598 A253599 A253600 * A253602 A253603 A253604

Keyword

nonn,base

Author

Michel Marcus, Jan 05 2015

Status

approved