A372362 a(n) is the 2-adic valuation of 1 + 3*{the n-th iterate of 27 with Reduced Collatz-function R}.

1, 2, 1, 1, 1, 1, 2, 2, 1, 2, 1, 1, 2, 1, 1, 1, 2, 3, 1, 1, 2, 1, 2, 1, 1, 1, 1, 1, 3, 1, 1, 1, 4, 2, 2, 4, 3, 1, 1, 5, 4, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2

Offset: 0

Author

Antti Karttunen, May 06 2024

Keywords

• nonn

Links

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

Crossrefs

Cf. A371093, A372443, A372447, A372448.

The first 41 terms form the row 13 of A351122.

Programs

PARI

A000265(n) = (n>>valuation(n,2));
A371093(n) = valuation(1+3*n,2);
A372443(n) = { my(x=27); while(n, x=A000265(3*x+1); n--); (x); };
A372362(n) = A371093(A372443(n));

Formula

a(n) = A371093(A372443(n)).