A374362 a(n) is the least term t of A005836 such that n - t also belongs to A005836.

0, 0, 1, 0, 0, 1, 3, 3, 4, 0, 0, 1, 0, 0, 1, 3, 3, 4, 9, 9, 10, 9, 9, 10, 12, 12, 13, 0, 0, 1, 0, 0, 1, 3, 3, 4, 0, 0, 1, 0, 0, 1, 3, 3, 4, 9, 9, 10, 9, 9, 10, 12, 12, 13, 27, 27, 28, 27, 27, 28, 30, 30, 31, 27, 27, 28, 27, 27, 28, 30, 30, 31, 36, 36, 37, 36

Offset: 0

Author

Rémy Sigrist, Jul 06 2024

Keywords

• nonn
• base

Comments

To compute a(n): in the ternary expansion of n, replace 1's by 0's and 2's by 1's.

Examples

			The first terms, in decimal and in ternary, are:
  n   a(n)  ter(n)  ter(a(n))
  --  ----  ------  ---------
   0     0       0          0
   1     0       1          0
   2     1       2          1
   3     0      10          0
   4     0      11          0
   5     1      12          1
   6     3      20         10
   7     3      21         10
   8     4      22         11
   9     0     100          0
  10     0     101          0
  11     1     102          1
  12     0     110          0
  13     0     111          0
  14     1     112          1
  15     3     120         10
		

Links

• Rémy Sigrist, Table of n, a(n) for n = 0..6561

Crossrefs

Cf. A005836, A289814, A374361.

Programs

PARI

a(n) = fromdigits(apply(d -> [0, 0, 1][1+d], digits(n, 3)), 3)

Python

from gmpy2 import digits
def A374362(n): return int(digits(n,3).replace('1','0').replace('2','1'),3) # Chai Wah Wu, Jul 09 2024

Formula

a(n) = A374361(n, 0).

a(n) = n - A374363(n).

a(n) >= 0 with equality iff n belongs to A374361.

a(n) = A005836(1 + A289814(n)).