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

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

Author

Labos Elemer, Apr 30 2003

Keywords

• easy
• nonn

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

• Vincenzo Librandi, Table of n, a(n) for n = 1..1000

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