A375216 n is the a(n)-th nonnegative integer having its multiset of binary digits.

1, 1, 1, 1, 1, 1, 2, 1, 1, 1, 2, 1, 3, 2, 3, 1, 1, 1, 2, 1, 3, 2, 3, 1, 4, 4, 5, 2, 6, 3, 4, 1, 1, 1, 2, 1, 3, 2, 3, 1, 4, 4, 5, 2, 6, 3, 4, 1, 5, 7, 8, 5, 9, 6, 7, 2, 10, 8, 9, 3, 10, 4, 5, 1, 1, 1, 2, 1, 3, 2, 3, 1, 4, 4, 5, 2, 6, 3, 4, 1, 5, 7, 8, 5, 9, 6, 7, 2, 10, 8, 9, 3, 10, 4, 5, 1, 6, 11, 12, 11, 13

Offset: 0

Author

Alois P. Heinz, Jan 30 2025

Keywords

• nonn
• look
• base

Examples

			a(26) = 5 because 26 is the 5th nonnegative integer having its multiset of binary digits: 19 = 10011_2, 21 = 10101_2, 22 = 10110_2, 25 = 11001_2, 26 = 11010_2.
		

Links

• Alois P. Heinz, Table of n, a(n) for n = 0..65536

Crossrefs

Cf. A073137.

Programs

Maple

p:= proc() 0 end:
a:= proc(n) option remember; local t;
      t:= sort(Bits[Split](n)); p(t):= p(t)+1
    end:
seq(a(n), n=0..100);

Formula

Ordinal transform of A073137.