OFFSET
1,2
COMMENTS
A self-inverse permutation of the natural numbers; a(n) = n if and only if A007931(n) is a palindrome.
The natural numbers written backwards digit-wise in bijective base-2 numeration, and interpreted forwards. - Harald Korneliussen, Apr 11 2019
LINKS
EXAMPLE
A007931 = (1,2,11,12,21,22,111,112,121,122,211,...); and (reversal of term #8) = term #11.
CROSSREFS
KEYWORD
AUTHOR
Clark Kimberling, Mar 11 2003
STATUS
approved