A331271 - OEIS

A331271

a(n) is the greatest divisor v of A331221(n) such that the decimal representations of v and of A331221(n)/v have the same number of digits d for d = 0..9.

%I #10 Jan 13 2020 18:25:43

%S 1,2,3,4,5,6,7,8,9,10,11,12,13,14,15,21,16,17,18,19,20,31,21,22,23,41,

%T 24,25,26,27,32,51,28,29,30,31,61,42,32,33,34,71,35,36,52,37,38,81,43,

%U 39,40,62,41,91,42,43,53,44,72,45,46,47,63,82,48,49,54

%N a(n) is the greatest divisor v of A331221(n) such that the decimal representations of v and of A331221(n)/v have the same number of digits d for d = 0..9.

%H Rémy Sigrist, <a href="/A331271/b331271.txt">Table of n, a(n) for n = 1..10000</a>

%F a(n) * A331270(n) = A331221(n).

%o (PARI) b=10; k=67; for (n=1, oo, fordiv (n, u, if (vecsort(digits(u,b))==vecsort(digits(v=n/u,b)), print1 (v", "); break (if (k--, 1, 2)))))

%Y Cf. A331221, A331270.

%K nonn,base

%O 1,2

%A _Rémy Sigrist_, Jan 13 2020