OFFSET
1,2
COMMENTS
wt(k) = A000120(k) is also called bitcount(k).
In other words, the positions of ones in A228085.
Numbers that can be expressed as the sum of distinct terms of the form 2^n+1, n=0,1,... in exactly one way. - Matthew C. Russell, Oct 08 2013
LINKS
FORMULA
EXAMPLE
0 is in this sequence because there is a unique k such that k+A000120(k)=0, in this case k=0.
1 is not in this sequence because there is no such k that k+A000120(k) would be 1. (Instead 1 is in A010061).
2 is in this sequence because there is exactly one k that satisfies k+A000120(k)=2, namely k=1.
3 is in this sequence because there is exactly one k that satisfies k+A000120(k)=3, namely k=2.
4 is not in this sequence because there is no such k that k+A000120(k) would be 4. (Instead 4 is in A010061.)
5 is not in this sequence because there is more than one k that satisfies k+A000120(k)=5, namely k=3 and k=4.
MAPLE
For Maple code see A230091. - N. J. A. Sloane, Oct 10 2013
PROG
(Scheme with Antti Karttunen's IntSeq-library)
(Haskell)
a228088 n = a228088_list !! (n-1)
a228088_list = 0 : filter ((== 1) . a228085) [1..]
-- Reinhard Zumkeller, Oct 13 2013
CROSSREFS
KEYWORD
nonn,base
AUTHOR
Antti Karttunen, Aug 09 2013
STATUS
approved