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A331270
a(n) is the least divisor u of A331221(n) such that the decimal representations of u and of A331221(n)/u have the same number of digits d for d = 0..9.
3
1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 12, 16, 17, 18, 19, 20, 13, 21, 22, 23, 14, 24, 25, 26, 27, 23, 15, 28, 29, 30, 31, 16, 24, 32, 33, 34, 17, 35, 36, 25, 37, 38, 18, 34, 39, 40, 26, 41, 19, 42, 43, 35, 44, 27, 45, 46, 47, 36, 28, 48, 49, 45
OFFSET
1,2
LINKS
FORMULA
a(n) * A331271(n) = A331221(n).
PROG
(PARI) b=10; k=67; for (n=1, oo, fordiv (n, u, if (vecsort(digits(u, b))==vecsort(digits(n/u, b)), print1 (u", "); break (if (k--, 1, 2)))))
CROSSREFS
Sequence in context: A366994 A365683 A057946 * A117657 A352529 A357434
KEYWORD
nonn,base
AUTHOR
Rémy Sigrist, Jan 13 2020
STATUS
approved