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.

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, 24, 25, 26, 27, 32, 51, 28, 29, 30, 31, 61, 42, 32, 33, 34, 71, 35, 36, 52, 37, 38, 81, 43, 39, 40, 62, 41, 91, 42, 43, 53, 44, 72, 45, 46, 47, 63, 82, 48, 49, 54

Offset

1,2

Links

Rémy Sigrist, Table of n, a(n) for n = 1..10000

Formula

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

Prog

(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)))))

Crossrefs

Cf. A331221, A331270.

Sequence in context: A052060 A084688 A194898 * A267016 A023769 A023796

Adjacent sequences: A331268 A331269 A331270 * A331272 A331273 A331274

Keyword

nonn,base

Author

Rémy Sigrist, Jan 13 2020

Status

approved