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

%I

%S 4,9,17,18,24,29,33,34,38,39,44,54,57,58,59,62,67,72,79,84,88,94,144,

%T 158,173,194,209,212,224,237,238,244,247,253,257,259,307,313,314,333,

%U 334,338,349,353,359,377,388,404,409,424,437,444,447,449,454,459,467

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

%H Iain Fox, <a href="/A253601/b253601.txt">Table of n, a(n) for n = 1..10000</a>

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

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

%o isok(n) = a253600(n) == 3;

%o (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

%Y Cf. A103173, A189056, A253600, A253602.

%K nonn,base

%O 1,1

%A _Michel Marcus_, Jan 05 2015

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Last modified September 28 11:24 EDT 2022. Contains 357070 sequences. (Running on oeis4.)