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A247045 Triangle read by rows: T(n,k) = least number m > 0 such that m^k in base n contains exactly k distinct digits, 1 <= k <= n. 1

%I #16 Feb 14 2017 11:09:07

%S 1,1,2,1,3,4,1,2,3,5,1,3,3,6,12,1,3,5,7,7,15,1,3,5,9,5,17,15,1,4,5,10,

%T 9,7,11,33,1,3,5,7,11,19,14,16,53,1,4,5,6,7,13,13,14,21,36,1,4,5,7,10,

%U 8,12,12,16,42,41,1,4,6,16,11,8,19,19,16,28,35,55,1,4,6,9,9,14,10,18,14

%N Triangle read by rows: T(n,k) = least number m > 0 such that m^k in base n contains exactly k distinct digits, 1 <= k <= n.

%H Indranil Ghosh, <a href="/A247045/b247045.txt">Rows 1..36 of triangle, flattened</a>

%e T(n,k) is given by (row n corresponds to base n):

%e 1;

%e 1, 2;

%e 1, 3, 4;

%e 1, 2, 3, 5;

%e 1, 3, 3, 6, 12;

%e 1, 3, 5, 7, 7, 15;

%e 1, 3, 5, 9, 5, 17, 15;

%e 1, 4, 5, 10, 9, 7, 11, 33;

%e 1, 3, 5, 7, 11, 19, 14, 16, 53;

%e 1, 4, 5, 6, 7, 13, 13, 14, 21, 36; (base 10)

%e 1, 4, 5, 7, 10, 8, 12, 12, 16, 42, 41;

%e Example: T(7,3) = 5 means that 5 is the smallest number such that 5^3 in base 7 (which is 125 in base 7 = 236) has 3 distinct digits (2, 3, and 6).

%o (PARI)

%o print1(1,", ");n=2;while(n<20,m=1;for(k=1,n,while(m,d=digits(m^k,n);if(#vecsort(d,,8)!=k,m++);if(#vecsort(d,,8)==k,print1(m,", ");m=1;break)));n++)

%Y Cf. A016069, A155146, A155150.

%K nonn,base,tabl

%O 1,3

%A _Derek Orr_, Sep 10 2014

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Last modified April 25 04:42 EDT 2024. Contains 371964 sequences. (Running on oeis4.)