A324557 Fixed points of A324556.

1, 5, 19, 34, 135, 261, 1028, 1032, 2054, 8203, 32777, 32785, 524320, 1048591, 1048592, 1048704, 2097162, 8388864, 16777235, 16777251, 268435521, 536870945, 536871169, 2147483712, 4294967809, 68719476749, 137438953984, 137438955520, 274877906967, 1099511627794

Offset

1,2

Comments

If f(n) denotes the binary tree representation of n defined in A324556, then this sequence lists the n such that f(n) is symmetrical.

Links

Luc Rousseau, Table of n, a(n) for n = 1..200

Luc Rousseau, A program to compute this sequence (SWI-Prolog).

Example

34 is '100010' in binary, which is a one, followed by 3 zeros, followed by '10' = 2. Then, following the rules specified in A324556, 34 can be represented by the partial decomposition tree:
          34
          / \
         2   3
Pursuing the decomposition process yields the complete decomposition tree:
          34
          / \
         /   \
        /     \
       /       \
      /         \
     2           3
    / \         / \
   0   1       1   0
      / \     / \
     0   0   0   0
With values removed, this tree is symmetrical. So, 34 is in the sequence.

Crossrefs

Cf. A324556.

Sequence in context: A243269 A252930 A031019 * A255413 A031041 A029523

Adjacent sequences: A324554 A324555 A324556 * A324558 A324559 A324560

Keyword

nonn,base

Author

Luc Rousseau, Mar 15 2019

Status

approved