A372447 a(n) = A000523(A372443(n)); One less than the binary length of the n-th iterate of 27 with Reduced Collatz-function R.

4, 5, 4, 5, 6, 6, 7, 6, 6, 7, 6, 7, 7, 7, 8, 8, 9, 8, 7, 7, 8, 8, 8, 8, 8, 9, 10, 10, 11, 9, 10, 11, 11, 9, 8, 8, 5, 4, 5, 5, 2, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0

Offset: 0

Author

Antti Karttunen, May 03 2024

Keywords

• nonn

Links

• Index entries for sequences related to 3x+1 (or Collatz) problem

Crossrefs

Cf. A000523, A372443.

Programs

PARI

A000265(n) = (n>>valuation(n,2));
A000523(n) = logint(n,2);
A372443(n) = { my(x=27); while(n, x=A000265(3*x+1); n--); (x); };
A372447(n) = A000523(A372443(n));