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A045817
Numbers n written in base 7, where in the list of divisors of n (in base 7), each digit 0-6 appears equally often.
2
3602, 246506, 264533, 266405, 303652, 320556, 324255, 325605, 342560, 345064, 345406, 345604, 346340, 362055, 414056, 430462, 434630, 435065, 436430, 436550, 453605, 500426, 500641, 506022, 524360, 524406, 526433, 530632, 532650, 533402
OFFSET
1,1
LINKS
EXAMPLE
E.g., divisors of 342560 (base 7) are (1,2,10,20,15463,34256,154630,342560) (all in base 7); the numbers of digits (0-6) are [0(4),1(4),2(4),3(4),4(4),5(4),6(4)].
MAPLE
N:= 7^6:
cv7:= proc(n) local L; L:= convert(n, base, 7);
add(L[i]*10^(i-1), i=1..nops(L)) end proc:
V:= Matrix(N, 7, datatype=integer[8]):
count:= 0: Res:= NULL:
for i from 1 to N do
L:= convert(i, base, 7);
M:= Vector[row]([seq(numboccur(d, L), d=0..6)], datatype=integer[8]);
for r from i to N by i do V[r, ..]:= V[r, ..] + M od;
if nops(convert(V[i, ..], set))=1 then
count:= count+1;
w:= cv7(i);
Res:= Res, w;
fi
od:
Res; # Robert Israel, Sep 07 2018
CROSSREFS
KEYWORD
easy,nonn,base
EXTENSIONS
Definition clarified by Robert Israel, Sep 07 2018
STATUS
approved