A336876 a(n) is the least m such that A336826(n) = m*p(m) (where p(m) is the product of decimal digits of m).

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, 112, 121, 25, 51, 33, 26, 42, 113, 61, 27, 131, 34, 211, 28, 114, 122, 71, 43, 52, 29, 35, 141, 115, 36, 116, 44, 123, 62, 151, 37, 132, 53, 91, 212, 221, 45, 38

Offset: 1

Author

Rémy Sigrist, Aug 06 2020

Keywords

• nonn
• look
• base

Comments

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.

Examples

			For n = 26:
- A336826(26) = 192,
- the divisors d of 192, alongside d*p(d), are:
  d    d*p(d)
  ---  ------
    1       1
    2       4
    3       9
    4      16
    6      36
    8      64
   12      24
   16      96
   24     192
   32     192
   48    1536
   64    1536
   96    5184
  192    3456
- so a(26) = min(24, 32) = 24.
		

Links

• Rémy Sigrist, Table of n, a(n) for n = 1..10000
• Rémy Sigrist, C program for A336876

Crossrefs

Cf. A007954, A098736, A336826, A336879.

Programs

C

See Links section.

Formula

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