A084054 5*n digit-reversed mod 5.

1, 1, 2, 2, 3, 3, 4, 4, 0, 0, 1, 1, 2, 2, 3, 3, 4, 4, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 3, 3, 3, 3, 3, 3, 3, 3, 3, 3, 3, 3, 3, 3, 3, 3, 3, 3, 3, 3, 4, 4, 4, 4, 4, 4, 4, 4, 4, 4, 4, 4, 4, 4, 4, 4, 4, 4, 4, 4, 0, 0, 0, 0, 0, 0, 0

Offset: 2

Author

Amarnath Murthy and Meenakshi Srikanth (menakan_s(AT)yahoo.com), May 26 2003

Keywords

• base
• easy
• nonn

Comments

The pattern of increasing frequency of repetition of digits is clear.

Examples

			a(61) =3 as, 61*5 = 305,digit reversed = 503 ==3 (mod 5)
		

Crossrefs

Cf. A084052, A084053, A084055, A084339, A084340, A084341.

Programs

Mathematica

Contribution from Enrique Pérez Herrero, Jun 14 2010: (Start)
A084054[n_Integer]:=Mod[FromDigits[Reverse[IntegerDigits[5*n]]],5];
(* Alternative formula *)
A084054[n_Integer]:=Mod[Floor[5*n/10^Floor[Log[10,5*n]]],5] (End)

Formula

Contribution from Enrique Pérez Herrero, Jun 14 2010: (Start)

a(n)=mod(floor(5*n/10^(floor(log_10(5*n)))),5), this formula comes from the modulus 5 of the first digit of 5*n.

a(10^n)=1

(End)

Extensions

More terms from Ray Chandler, May 27 2003