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.

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A361833 Fixed points of A361832.

Original entry on oeis.org

0, 1, 2, 4, 8, 12, 13, 14, 24, 25, 26, 37, 40, 43, 74, 77, 80, 111, 112, 113, 120, 121, 122, 129, 130, 131, 222, 223, 224, 231, 232, 233, 240, 241, 242, 334, 336, 341, 362, 364, 366, 387, 392, 394, 668, 670, 672, 693, 698, 700, 721, 723, 728, 1002, 1003, 1004
Offset: 1

Views

Author

Rémy Sigrist, Mar 26 2023

Keywords

Comments

This sequence is infinite as it contains A048328.
If v is a term, then floor(v/3) is also a term.
Empirically, for any w > 0, there are A117855(w) positive terms with w ternary digits.

Examples

			A361832(12) = 12 so 12 belongs to the sequence.
A361832(11) = 15 so 11 does not belong to the sequence.
		

Crossrefs

Programs

  • PARI
    See Links section.

A371635 For any number k >= 0, let T_k be the triangle with values in {-1, 0, +1} whose base corresponds to the balanced ternary expansion of k (without leading zeros) and other values, say t above u and v, satisfy t+u+v = 0 mod 3; the balanced ternary expansion of a(n) corresponds to the left border of T_n (the most significant digit being at the bottom left corner).

Original entry on oeis.org

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

Views

Author

Rémy Sigrist, Mar 30 2024

Keywords

Comments

This sequence is a variant of A334727 and A361832.
This sequence is a self-inverse permutation of the nonnegative integers.

Examples

			For n = 42: the balanced ternary expansion of 42 is "1TTT0" (where T denotes -1), and T_42 is as follows:
         T
        0 1
       1 T 0
      0 T T 1
     1 T T T 0
So the balanced ternary expansion of a(42) is "1010T", and a(42) = 89.
		

Crossrefs

Programs

  • PARI
    a(n) = { my (b = [], d); while (n, b = concat(d = Mod(n, 3), b); n = (n-centerlift(d)) / 3;); my (t = vector(#b)); for (i = 1, #t, t[i] = centerlift(b[1]); b = -vector(#b-1, j, b[j]+b[j+1]);); fromdigits(t, 3); }
Showing 1-2 of 2 results.