A070644 a(n) = n^6 mod 21.

0, 1, 1, 15, 1, 1, 15, 7, 1, 15, 1, 1, 15, 1, 7, 15, 1, 1, 15, 1, 1, 0, 1, 1, 15, 1, 1, 15, 7, 1, 15, 1, 1, 15, 1, 7, 15, 1, 1, 15, 1, 1, 0, 1, 1, 15, 1, 1, 15, 7, 1, 15, 1, 1, 15, 1, 7, 15, 1, 1, 15, 1, 1, 0, 1, 1, 15, 1, 1, 15, 7, 1, 15, 1, 1, 15, 1, 7, 15, 1, 1, 15, 1, 1, 0, 1, 1, 15, 1, 1

Offset

0,4

Links

Table of n, a(n) for n=0..89.

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

Formula

a(n) = a(n-21). - Wesley Ivan Hurt, Dec 26 2023

Mathematica

PowerMod[Range[0, 90], 6, 21] (* or *) PadRight[{}, 90, {0, 1, 1, 15, 1, 1, 15, 7, 1, 15, 1, 1, 15, 1, 7, 15, 1, 1, 15, 1, 1}] (* Harvey P. Dale, Aug 10 2019 *)

Prog

(Sage) [power_mod(n, 6, 21)for n in range(0, 90)] # Zerinvary Lajos, Nov 06 2009
(PARI) a(n)=n^6%21 \\ Charles R Greathouse IV, Apr 06 2016

Crossrefs

Sequence in context: A040226 A172429 A040225 * A174389 A176286 A111805

Adjacent sequences: A070641 A070642 A070643 * A070645 A070646 A070647

Keyword

nonn,easy

Author

N. J. A. Sloane, May 13 2002

Status

approved