1,3

The values of k's are sorted here according to the magnitude of the sum k + bitcount(k), where bitcount(k) (= A000120) gives the number of 1's in binary representation of nonnegative integer k; a(n) = A228086(A228088(n)).

Antti Karttunen, Table of n, a(n) for n = 1..10000

Index entries for Colombian or self numbers and related sequences

a(n) = A228086(A228088(n)).

A092391(a(n)) = A228088(n).

6 is in this sequence because the sum 6+A000120(6)=8 cannot be obtained with any other value of k than k=6.

8 is in this sequence because the sum 8+A000120(8)=9 cannot be obtained with any other value of k than k=8.

7 is in this sequence because the sum 7+A000120(7)=10 cannot be obtained with any other value of k than k=7.

In this sequence 8 becomes before 7 because 8+A000120(8) < 7+A000120(7).

(Scheme) (define (A228089 n) (A228086 (A228088 n)))

A228090 gives the same terms sorted into ascending order.

Sequence in context: A033959 A167455 A159752 * A126971 A175354 A224778

Adjacent sequences: A228086 A228087 A228088 * A228090 A228091 A228092

nonn

Antti Karttunen, Aug 17 2013

approved