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.

Showing 1-3 of 3 results.

A083528 a(n) = 5^n mod 2*n.

Original entry on oeis.org

1, 1, 5, 1, 5, 1, 5, 1, 17, 5, 5, 1, 5, 25, 5, 1, 5, 1, 5, 25, 41, 25, 5, 1, 25, 25, 53, 9, 5, 25, 5, 1, 59, 25, 45, 1, 5, 25, 47, 65, 5, 1, 5, 9, 35, 25, 5, 1, 19, 25, 23, 1, 5, 1, 45, 81, 11, 25, 5, 25, 5, 25, 125, 1, 5, 49, 5, 81, 125, 65, 5, 1, 5, 25, 125, 17, 3, 25, 5, 65, 161, 25, 5, 1, 65
Offset: 1

Views

Author

Labos Elemer, Apr 30 2003

Keywords

Comments

a(n) = 1 iff n is in A067946. - Robert Israel, Dec 26 2014

Examples

			a(3) = 5 because 5^3 = 125 and 125 == 5 mod (2 * 3).
a(4) = 1 because 5^4 = 625 and 625 == 1 mod (2 * 4).

Links

Crossrefs

Cf. A000079, A000244, A000351, A000420, A082511.
Cf. A067946, A083529, A083530.

Programs

  • Magma
    [Modexp(5, n, 2*n): n in [1..80]]; // Vincenzo Librandi, Oct 19 2018
  • Maple
    seq(5 &^n mod (2*n), n = 1 .. 100); # Robert Israel, Dec 26 2014
  • Mathematica
    Table[PowerMod[5, w, 2w], {w, 1, 100}]
  • PARI
    vector(100, n, lift(Mod(5, 2*n)^n)) \\ Michel Marcus, Dec 29 2014

A083529 a(n) = 5^n mod 3*n.

Original entry on oeis.org

2, 1, 8, 1, 5, 1, 5, 1, 26, 25, 5, 1, 5, 25, 35, 1, 5, 1, 5, 25, 62, 25, 5, 1, 50, 25, 80, 37, 5, 55, 5, 1, 26, 25, 80, 1, 5, 25, 8, 25, 5, 1, 5, 97, 80, 25, 5, 1, 68, 25, 125, 1, 5, 1, 155, 25, 125, 25, 5, 145, 5, 25, 188, 1, 5, 181, 5, 13, 125, 205, 5, 1, 5, 25, 125, 169, 80, 181, 5
Offset: 1

Views

Author

Labos Elemer, Apr 30 2003

Keywords

Comments

From Robert Israel, Dec 25 2014: (Start)
a(n) == (-1)^n mod 3.
a(n) = 1 if and only if n is even and in A067946.
For n > 3, a(n) = 5 if and only if n is odd and in A123091. (End)

Examples

			a(3) = 8 because 5^3 = 125 and 125 mod (3 * 3) = 8.
a(4) = 1 because 5^4 = 625 and 625 mod (3 * 4) = 1.

Links

Crossrefs

Cf. A000079, A000244, A000351, A000420, A082511, A083528, A083530, A067946, A123091.

Programs

A083530 a(n) = 7^n mod (2*n).

Original entry on oeis.org

1, 1, 1, 1, 7, 1, 7, 1, 1, 9, 7, 1, 7, 21, 13, 1, 7, 1, 7, 1, 7, 5, 7, 1, 7, 49, 1, 49, 7, 49, 7, 1, 13, 49, 63, 1, 7, 49, 31, 1, 7, 49, 7, 25, 37, 49, 7, 1, 49, 49, 37, 9, 7, 1, 43, 49, 1, 49, 7, 1, 7, 49, 91, 1, 37, 37, 7, 89, 67, 49, 7, 1, 7, 49, 43, 121, 105, 25, 7, 1, 1, 49, 7, 49, 147, 49
Offset: 1

Views

Author

Labos Elemer, Apr 30 2003

Keywords

Examples

			For n = 5, a(5) = 7 because 7^5 = 16807 = 1680*10 + 7, that is 7^5 == 7 (mod 2*5).

Links

Crossrefs

Cf. A000079, A000244, A000351, A000420, A082511, A083528, A083529.

Programs

  • Mathematica
    Table[Mod[7^w, 2*w], {w, 1, 100}]
  • PARI
    a(n)=lift(Mod(7,2*n)^n) \\ Charles R Greathouse IV, Oct 03 2016
Showing 1-3 of 3 results.

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