OFFSET
1,1
COMMENTS
Recursion into A342369 means tracing the Collatz tree backward, starting at k = A342369(6*n-2), then k = A342369(k) until k is divisible by 3. At each A342369(k) = 3*m - 1, a new side-branch is connected which would start at 6*m-2. If A342369(k) reached a value divisible by three no further side-branches will be found.
This sequence is a rearrangement of A087088 such that all values at positions divisible by 3 are unchanged.
LINKS
FORMULA
EXAMPLE
n = 2:
6*n-2 = 10.
A342369(10) = 20. -> 7*3 - 1 -> A side-branch is connected.
A342369(20) = 13.
A342369(13) = 26. -> 9*3 - 1 -> A side-branch is connected.
A342369(26) = 17. -> 6*3 - 1 -> A side-branch is connected.
A342369(17) = 11. -> 4*3 - 1 -> A side-branch is connected.
A342369(11) = 7.
A342369(7) = 14. -> 5*3 - 1 -> A side-branch is connected.
A342369(14) = 9. -> divisible by 3 we stop here.
-> We found 5 connected side-branches, a(2) = 5.
PROG
CROSSREFS
KEYWORD
nonn
AUTHOR
Thomas Scheuerle, Mar 24 2021
STATUS
approved