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

0,7

Comments

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

Links

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

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)).

Example

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

Prog

(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

Crossrefs

Cf. A005836, A289814, A374361.

Sequence in context: A230667 A131462 A230811 * A371274 A117032 A243823

Adjacent sequences: A374359 A374360 A374361 * A374363 A374364 A374365

Keyword

nonn,base

Author

Rémy Sigrist, Jul 06 2024

Status

approved