A248357 Numbers k such that A248355(k+1) = A248355(k) + 1.

1, 2, 3, 4, 6, 7, 9, 11, 13, 16, 19, 21, 24, 28, 31, 34, 38, 42, 46, 51, 55, 60, 65, 70, 75, 81, 87, 93, 99, 105, 111, 118, 125, 132, 139, 147, 154, 162, 170, 178, 187, 195

Offset: 1

Author

Clark Kimberling, Oct 05 2014

Keywords

• nonn
• easy

Comments

The difference sequence of A248355 is (1, 1, 1, 1, 0, 1, 1, 0, 1, 0, 1, 0, 1, 0, 0, 1, 0, 0, 1,...), so that A248356 = (5, 8, 10, 12, 14, 15, ...) and A248357 = (1, 2, 3, 4, 6, 7, 9, 11, 13, 16, 19,...); A248356 and A248357 are a complementary pair.

Links

• Clark Kimberling, Table of n, a(n) for n = 1..300

Crossrefs

Cf. A248355, A248356, A248358, A248347.

Programs

Mathematica

z = 200; p[k_] := p[k] = k*Sin[Pi/k]; N[Table[Pi - p[n], {n, 1, z/10}]]
f[n_] := f[n] = Select[Range[z], Pi - p[#] < 1/(2 n) &, 1]
u = Flatten[Table[f[n], {n, 1, z}]]        (* A248355 *)
v = Flatten[Position[Differences[u], 0]]   (* A248356 *)
w = Flatten[Position[Differences[u], 1]]   (* A248357 *)
f = Table[Floor[1/(Pi - p[n])], {n, 1, z}] (* A248358 *)