A088666 a(n) = (n^4 + 1) mod 10.

1, 2, 7, 2, 7, 6, 7, 2, 7, 2, 1, 2, 7, 2, 7, 6, 7, 2, 7, 2, 1, 2, 7, 2, 7, 6, 7, 2, 7, 2, 1, 2, 7, 2, 7, 6, 7, 2, 7, 2, 1, 2, 7, 2, 7, 6, 7, 2, 7, 2, 1, 2, 7, 2, 7, 6, 7, 2, 7, 2, 1, 2, 7, 2, 7, 6, 7, 2, 7, 2, 1, 2, 7, 2, 7, 6, 7, 2, 7, 2, 1, 2, 7, 2, 7, 6, 7, 2, 7, 2

Offset

0,2

Comments

Periodic, with period 10. - Harvey P. Dale, Jan 31 2015

Links

Harvey P. Dale, Table of n, a(n) for n = 0..1000

Index entries for linear recurrences with constant coefficients, signature (0, 0, 0, 0, 0, 0, 0, 0, 0, 1).

Formula

a(n) = A010879(A002523(n)). - Michel Marcus, Feb 01 2015

Mathematica

PowerMod[Range[0, 90], 4, 10]+1 (* or *) PadRight[{}, 100, {1, 2, 7, 2, 7, 6, 7, 2, 7, 2}] (* Harvey P. Dale, Jan 31 2015 *)
LinearRecurrence[{0, 0, 0, 0, 0, 0, 0, 0, 0, 1}, {1, 2, 7, 2, 7, 6, 7, 2, 7, 2}, 90] (* Ray Chandler, Aug 26 2015 *)

Prog

(Magma) [(n^4+1) mod 10: n in [0..100]]; // Vincenzo Librandi, Feb 01 2015

Crossrefs

Cf. A010879 (n mod 10), A002523 (n^4+1).

Sequence in context: A262083 A181284 A010697 * A170854 A215140 A278419

Adjacent sequences: A088663 A088664 A088665 * A088667 A088668 A088669

Keyword

easy,nonn

Author

Cino Hilliard, Nov 23 2003

Extensions

Edited by Don Reble, May 03 2006

Name clarified by Vincenzo Librandi, Feb 01 2015

Status

approved