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A104686
a(n) = n*(n+1)/2 (mod 6).
1
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
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
KEYWORD
easy,nonn
AUTHOR
Stuart M. Ellerstein (ellerstein(AT)aol.com), Apr 22 2005
STATUS
approved