login
A338248
Nonnegative values in A053985, in order of appearance.
4
0, 1, 4, 5, 2, 3, 16, 17, 14, 15, 20, 21, 18, 19, 8, 9, 6, 7, 12, 13, 10, 11, 64, 65, 62, 63, 68, 69, 66, 67, 56, 57, 54, 55, 60, 61, 58, 59, 80, 81, 78, 79, 84, 85, 82, 83, 72, 73, 70, 71, 76, 77, 74, 75, 32, 33, 30, 31, 36, 37, 34, 35, 24, 25, 22, 23, 28, 29
OFFSET
0,3
COMMENTS
This sequence is a self-inverse permutation of the nonnegative integers (the offset has been set to 0 so as to get a permutation).
There are only two fixed points: a(0) = 0 and a(1) = 1.
FORMULA
a(0) = 0.
a(n) = A053985(A053738(n)) for any n > 0.
EXAMPLE
A053985 = 0, 1, -2, -1, 4, 5, 2, 3, -8, -7, -10, -9, -4, -3, -6, -5, 16, 17, ...
We keep: 0, 1, 4, 5, 2, 3, 16, 17, ...
PROG
(PARI) A053985(n) = fromdigits(binary(n), -2)
print (select(v -> v>=0, apply(A053985, [0..109])))
CROSSREFS
See A338245 for a similar sequence.
Sequence in context: A216252 A335615 A328622 * A328623 A225901 A354469
KEYWORD
nonn,base
AUTHOR
Rémy Sigrist, Oct 18 2020
STATUS
approved