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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A230856 Numbers n such that m + (sum of digits in base-3 representation of m) = n has exactly four solutions.

Original entry on oeis.org

248, 492, 978, 1222, 1708, 1952, 2192, 2196, 2436, 2680, 3166, 3410, 3896, 4140, 4380, 4384, 4624, 4868, 5354, 5598, 6084, 6328, 6566, 6572, 6810, 7054, 7540, 7784, 8270, 8514, 8754, 8758, 8998, 9242, 9728, 9972, 10458, 10702, 10942, 10946, 11186, 11430, 11916, 12160, 12646, 12890, 13128
Offset: 1

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Author

N. J. A. Sloane, Oct 31 2013

Keywords

Crossrefs

Related base-3 sequences: A053735, A134451, A230641, A230642, A230643, A230853, A230854, A230855, A230856, A230639, A230640, A010063 (trajectory of 1)

A230865 a(n) = n + (sum of digits in base-5 representation of n).

Original entry on oeis.org

0, 2, 4, 6, 8, 6, 8, 10, 12, 14, 12, 14, 16, 18, 20, 18, 20, 22, 24, 26, 24, 26, 28, 30, 32, 26, 28, 30, 32, 34, 32, 34, 36, 38, 40, 38, 40, 42, 44, 46, 44, 46, 48, 50, 52, 50, 52, 54, 56, 58, 52, 54, 56, 58, 60, 58, 60, 62, 64, 66, 64, 66, 68, 70, 72, 70, 72, 74, 76, 78, 76, 78, 80, 82, 84, 78, 80, 82, 84, 86, 84
Offset: 0

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Author

N. J. A. Sloane, Nov 05 2013

Keywords

Comments

The image of this sequence is the set of nonnegative even numbers (A005843). Joshi (1973) proved that the sequence of base-q self numbers (analogous to A003052) is the sequence of odd numbers (A005408) for all odd q. - Amiram Eldar, Nov 28 2020

References

  • V. S. Joshi, Ph.D. dissertation, Gujarat Univ., Ahmedabad (India), October, 1973.
  • József Sándor and Borislav Crstici, Handbook of Number theory II, Kluwer Academic Publishers, 2004, Chapter 4, p. 384-386.

Crossrefs

Programs

  • Mathematica
    Table[n + Plus @@ IntegerDigits[n, 5], {n, 0, 100}] (* Amiram Eldar, Nov 28 2020 *)

Formula

a(n) = n + A053824(n). - Amiram Eldar, Nov 28 2020

A350229 a(n) is the sum of n and the balanced ternary digits in n.

Original entry on oeis.org

0, 2, 2, 4, 6, 4, 6, 8, 8, 10, 12, 12, 14, 16, 12, 14, 16, 16, 18, 20, 20, 22, 24, 22, 24, 26, 26, 28, 30, 30, 32, 34, 32, 34, 36, 36, 38, 40, 40, 42, 44, 38, 40, 42, 42, 44, 46, 46, 48, 50, 48, 50, 52, 52, 54, 56, 56, 58, 60, 58, 60, 62, 62, 64, 66, 66, 68
Offset: 0

Views

Author

Rémy Sigrist, Jan 09 2022

Keywords

Comments

The image of this sequence is the set of nonnegative even numbers (A005843).

Examples

			For n = 42:
- the balanced ternary representation of 42 is "1TTT0",
- so a(42) = 42 + 1 - 1 - 1 - 1 + 0 = 40.
		

Crossrefs

See A062028, A092391, A230641 for similar sequences.
Cf. A005843, A065363, A174658 (fixed points).

Programs

  • Mathematica
    Array[# + Total[If[First@ # == 0, Rest@ #, #] &[Prepend[IntegerDigits[#, 3], 0] //. {x___, y_, k_ /; k > 1, z___} :> {x, y + 1, k - 3, z}]] &, 70, 0] (* Michael De Vlieger, Jan 15 2022 *)
  • PARI
    a(n) = my (v=n, d); while (n, n=(n-d=[0,1,-1][1+n%3])/3; v+=d); v

Formula

a(n) = n + A065363(n).
a(n) = n iff n belongs to A174658.
Previous Showing 11-13 of 13 results.