cp's OEIS Frontend

This is a front-end for the Online Encyclopedia of Integer Sequences, made by Christian Perfect. The idea is to provide OEIS entries in non-ancient HTML, and then to think about how they're presented visually. The source code is on GitHub.

A341054 For any number n with balanced ternary expansion (d_1, ..., d_k), the balanced ternary expansion of a(n), say (t_1, ..., t_k), satisfies t_m = d_1 + ... + d_m mod 3 for m = 1..k.

Original entry on oeis.org

0, 1, 3, 4, 2, 8, 9, 10, 12, 13, 11, 7, 5, 6, 25, 23, 24, 26, 27, 28, 30, 31, 29, 35, 36, 37, 39, 40, 38, 34, 32, 33, 21, 22, 20, 16, 14, 15, 17, 18, 19, 75, 76, 74, 70, 68, 69, 71, 72, 73, 79, 77, 78, 80, 81, 82, 84, 85, 83, 89, 90, 91, 93, 94, 92, 88, 86, 87
Offset: 0

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Author

Rémy Sigrist, Apr 25 2021

Keywords

Comments

This sequence is similar to A006068.
This sequence is a permutation of the nonnegative integers with inverse A341055.

Examples

			The first terms, alongside their balanced ternary expansion (with T's standing for -1's), are:
  n   a(n)  bter(n)  bter(a(n))
  --  ----  -------  ----------
   0     0        0           0
   1     1        1           1
   2     3       1T          10
   3     4       10          11
   4     2       11          1T
   5     8      1TT         10T
   6     9      1T0         100
   7    10      1T1         101
   8    12      10T         110
   9    13      100         111
  10    11      101         11T
  11     7      11T         1T1
  12     5      110         1TT
  13     6      111         1T0
  14    25     1TTT        10T1
  15    23     1TT0        10TT
  16    24     1TT1        10T0
		

Crossrefs

Cf. A006068, A059095, A341055 (inverse).

Programs

  • PARI
    a(n) = { my (d=[], s=Mod(0, 3)); while (n, my (t=centerlift(Mod(n, 3))); n=(n-t)\3; d=concat(t, d)); for (k=1, #d, d[k] = centerlift(s+=d[k])); fromdigits(d, 3) }