OFFSET
1,3
COMMENTS
Sequence contains ever-longer copies of A004760. - Ralf Stephan, Sep 16 2003
LINKS
Paolo Xausa, Table of n, a(n) for n = 1..10000
FORMULA
a(n) = n if 3*2^(k-1) <= n < 2^(k+1);
a(n) = a(n - 2^(k-1)) if 2^k <= n < 3*2^(k-1).
a(2n) = 2a(n) - [a(n)==1], a(2n+1) = 2a(n) + 1. - Ralf Stephan, Sep 16 2003
EXAMPLE
a(22)=14 because starting with 10110 the left rotation produces 01101 written as 1101 (i.e., 13) and the right rotation produces 1110 (i.e., 14).
MATHEMATICA
rtt[f_, n_] := FromDigits[f[IntegerDigits[n, 2]], 2];
Array[rtt[RotateRight, rtt[RotateLeft, #]]&, 100] (* Paolo Xausa, Jan 16 2024 *)
PROG
(PARI) a(n) = n-=1<<logint(n, 2); n + 1<<if(n, logint(n, 2)+1); \\ Kevin Ryde, Jan 13 2024
CROSSREFS
KEYWORD
nonn,base,easy
AUTHOR
Henry Bottomley, Mar 22 2000
STATUS
approved