A112282 a(n) = (-1)^n*(2*n+1) (mod 9).

1, 6, 5, 2, 0, 7, 4, 3, 8, 8, 3, 4, 7, 0, 2, 5, 6, 1, 1, 6, 5, 2, 0, 7, 4, 3, 8, 8, 3, 4, 7, 0, 2, 5, 6, 1, 1, 6, 5, 2, 0, 7, 4, 3, 8, 8, 3, 4, 7, 0, 2, 5, 6, 1, 1, 6, 5, 2, 0, 7, 4, 3, 8, 8, 3, 4, 7, 0, 2, 5, 6, 1, 1, 6, 5, 2, 0, 7, 4, 3, 8, 8, 3, 4, 7, 0, 2, 5, 6, 1, 1, 6, 5, 2, 0, 7, 4, 3, 8, 8, 3, 4, 7, 0, 2

Offset

0,2

Links

Table of n, a(n) for n=0..104.

Formula

Period 18 sequence: [1, 6, 5, 2, 0, 7, 4, 3, 8, 8, 3, 4, 7, 0, 2, 5, 6, 1].

Maple

seq(`mod`((-1)^n*(2*n+1), 9), n = 0..120); # G. C. Greubel, Nov 05 2019

Mathematica

Table[Mod[(-1)^n*(2*n+1), 9], {n, 0, 120}] (* G. C. Greubel, Nov 05 2019 *)
Mod[Times@@@Partition[Riffle[Range[1, 221, 2], {1, -1}, {1, -1, 2}], 2], 9] (* Harvey P. Dale, Jan 06 2024 *)

Prog

(PARI) a(n)=((-1)^n*(2*n+1))%9
(Magma) [(-1)^n*(2*n+1) mod 9 : n in [0..120]]; // G. C. Greubel, Nov 05 2019
(Sage) [mod((-1)^n*(2*n+1), 9) for n in (0..120)] # G. C. Greubel, Nov 05 2019
(GAP) List([0..120], n-> (-1)^n*(2*n+1) mod 9 ); # G. C. Greubel, Nov 05 2019

Crossrefs

Cf. A112280.

Sequence in context: A102079 A177938 A374529 * A098866 A144689 A221215

Adjacent sequences: A112279 A112280 A112281 * A112283 A112284 A112285

Keyword

nonn

Author

Paul D. Hanna, Sep 01 2005

Status

approved