A248611 - OEIS

%I #4 Oct 15 2014 21:02:00

%S 1,3,5,8,11,14,18,22,26,30,34,38,42,47,51,55,60,64,69,73,78,82,87,91,

%T 96,100,105,110,114,119,123,128,133,137,142,147,151,156,161,165,170,

%U 175,179,184,189,193,198,203,207,212,217,221,226,231,236,240,245

%N Numbers k such that A248610(k+1) = A248610(k).

%H Clark Kimberling, <a href="/A248611/b248611.txt">Table of n, a(n) for n = 1..400</a>

%e (A248610(k+1) - A248610(k)) = (0, 1, 0, 1, 0, 1, 1, 0, 1, 1, 0, 1, 1, 0, 1, 1, 1, 0, ...), so that A248611 = (1, 3, 5, 8, 11, 14, 18, 22, 26, ..) and A248612 = (2, 4, 6, 7, 9, 10, 12, 13, ...).

%t z = 300; p[k_] := p[k] = Sum[1/((h^2)*Binomial[2 h, h]), {h, 1, k}]

%t d = N[Table[Pi^2/18 - p[k], {k, 1, z/5}], 12]

%t f[n_] := f[n] = Select[Range[z], Pi^2/18 - p[#] < 1/3^n &, 1]

%t u = Flatten[Table[f[n], {n, 1, z}]]  (* A248610 *)

%t d = Differences[u]

%t v = Flatten[Position[d, 0]]  (* A248611 *)

%t w = Flatten[Position[d, 1]]  (* A248612 *)

%Y Cf. A248610, A248612, A248607.

%K nonn,easy

%O 1,2

%A _Clark Kimberling_, Oct 10 2014