A104686 a(n) = n*(n+1)/2 (mod 6).

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

Offset

0,3

Links

Table of n, a(n) for n=0..86.

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

Formula

a(n) = A010875(A000217(n)). - Arkadiusz Wesolowski, Nov 28 2011

G.f.: -x*(1+3*x+3*x^3+3*x^5+x^6) / ( (x-1)*(1+x+x^2)*(x^2+1)*(x^4-x^2+1) ). - R. J. Mathar, Oct 16 2015

Mathematica

Table[Mod[(n^2 + n)/2, 6], {n, 0, 100}] (* Arkadiusz Wesolowski, Nov 28 2011 *)
Mod[Accumulate[Range[0, 90]], 6] (* or *) LinearRecurrence[{0, 0, 1, 0, 0, -1, 0, 0, 1}, {0, 1, 3, 0, 4, 3, 3, 4, 0}, 90] (* Harvey P. Dale, Aug 21 2022 *)

Crossrefs

Sequence in context: A108572 A322335 A245907 * A301428 A104514 A349915

Adjacent sequences: A104683 A104684 A104685 * A104687 A104688 A104689

Keyword

easy,nonn

Author

Stuart M. Ellerstein (ellerstein(AT)aol.com), Apr 22 2005

Status

approved