A336876 - OEIS

%I #24 Aug 06 2020 16:02:44

%S 0,1,2,3,11,4,12,5,6,13,21,7,14,8,15,9,22,31,16,111,17,23,18,41,19,24,

%T 112,121,25,51,33,26,42,113,61,27,131,34,211,28,114,122,71,43,52,29,

%U 35,141,115,36,116,44,123,62,151,37,132,53,91,212,221,45,38

%N a(n) is the least m such that A336826(n) = m*p(m) (where p(m) is the product of decimal digits of m).

%C Some terms of A336826 have several representations as the product of a number and of its decimal digits; for example 549504 has four such representations: 1696 * 1 * 6 * 9 * 6, 2862 * 2 * 8 * 6 * 2, 3392 * 3 * 3 * 9 * 2 and 3816 * 3 * 8 * 1 * 6.

%H Rémy Sigrist, <a href="/A336876/b336876.txt">Table of n, a(n) for n = 1..10000</a>

%H Rémy Sigrist, <a href="/A336876/a336876.txt">C program for A336876</a>

%F A098736(a(n)) = A336826(n).

%e For n = 26:

%e - A336826(26) = 192,

%e - the divisors d of 192, alongside d*p(d), are:

%e   d    d*p(d)

%e   ---  ------

%e     1       1

%e     2       4

%e     3       9

%e     4      16

%e     6      36

%e     8      64

%e    12      24

%e    16      96

%e    24     192

%e    32     192

%e    48    1536

%e    64    1536

%e    96    5184

%e   192    3456

%e - so a(26) = min(24, 32) = 24.

%o (C) See Links section.

%Y Cf. A007954, A098736, A336826, A336879.

%K nonn,look,base

%O 1,3

%A _Rémy Sigrist_, Aug 06 2020