A374363 a(n) is the greatest term t <= n of A005836 such that n - t also belongs to A005836.

0, 1, 1, 3, 4, 4, 3, 4, 4, 9, 10, 10, 12, 13, 13, 12, 13, 13, 9, 10, 10, 12, 13, 13, 12, 13, 13, 27, 28, 28, 30, 31, 31, 30, 31, 31, 36, 37, 37, 39, 40, 40, 39, 40, 40, 36, 37, 37, 39, 40, 40, 39, 40, 40, 27, 28, 28, 30, 31, 31, 30, 31, 31, 36, 37, 37, 39, 40

Offset

0,4

Comments

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

Links

Rémy Sigrist, Table of n, a(n) for n = 0..6560

Formula

a(n) = T(n, A120880(k)-1).

a(n) = n - A374362(n).

a(n) <= n with equality iff n belongs to A005836.

a(n) = A005836(1+A289831(n)).

Example

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

Prog

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

Crossrefs

Cf. A005836, A120880, A289831, A374361, A374362.

Sequence in context: A276865 A253718 A350188 * A295570 A035004 A222290

Adjacent sequences: A374360 A374361 A374362 * A374364 A374365 A374366

Keyword

nonn,base

Author

Rémy Sigrist, Jul 06 2024

Status

approved