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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).
7
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
1,3
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.
LINKS
FORMULA
A098736(a(n)) = A336826(n).
EXAMPLE
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.
PROG
(C) See Links section.
CROSSREFS
KEYWORD
nonn,look,base
AUTHOR
Rémy Sigrist, Aug 06 2020
STATUS
approved