login
A331266
a(n) is the least divisor u of A331219(n) such that the binary representations of u and of A331219(n)/u have the same number of 0's and the same number of 1's.
3
1, 2, 3, 4, 5, 5, 6, 7, 8, 9, 9, 10, 9, 10, 11, 11, 12, 11, 13, 13, 14, 15, 16, 17, 17, 18, 17, 18, 19, 19, 20, 17, 19, 18, 21, 21, 19, 20, 22, 19, 21, 23, 19, 21, 22, 22, 24, 21, 22, 23, 25, 25, 23, 26, 23, 25, 26, 27, 27, 28, 27, 29, 29, 30, 31, 32, 33, 33
OFFSET
1,2
LINKS
FORMULA
a(n) * A331267(n) = A331219(n).
PROG
(PARI) b=2; k=68; 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: A163296 A247971 A317334 * A172103 A123731 A247973
KEYWORD
nonn,base
AUTHOR
Rémy Sigrist, Jan 13 2020
STATUS
approved