A194379 Numbers m such that Sum_{k=1..m} (<1/2 + k*r> - ) = 0, where r=sqrt(7) and < > denotes fractional part.

2, 14, 16, 28, 30, 32, 34, 36, 42, 44, 46, 48, 50, 62, 64, 76, 78, 80, 82, 84, 90, 92, 94, 96, 98, 110, 112, 124, 126, 128, 130, 132, 138, 140, 142, 144, 146, 158, 160, 172, 174, 176, 178, 180, 186, 188, 190, 192, 194, 206, 208, 220, 222, 224, 226, 228

Offset: 1

Author

Clark Kimberling, Aug 23 2011

Keywords

• nonn

Comments

All the terms are even. See A194368.

Examples

			r = Sqrt[7]; c = 1/2;
		

Crossrefs

Cf. A194368.

Programs

Mathematica

x[n_] := Sum[FractionalPart[k*r], {k, 1, n}]
y[n_] := Sum[FractionalPart[c + k*r], {k, 1, n}]
t1 = Table[If[y[n] < x[n], 1, 0], {n, 1, 100}];
Flatten[Position[t1, 1]]   (* A194378 *)
t2 = Table[If[y[n] == x[n], 1, 0], {n, 1, 300}];
Flatten[Position[t2, 1]]  (* A194379 *)
t3 = Table[If[y[n] > x[n], 1, 0], {n, 1, 800}];
Flatten[Position[t3, 1]]   (* A194380 *)