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A248608 Numbers k such that A248607(k+1) = A248607(k) + 1. 4
1, 3, 5, 7, 9, 11, 13, 15, 17, 20, 22, 24, 26, 29, 31, 33, 35, 38, 40, 42, 45, 47, 49, 52, 54, 56, 59, 61, 63, 66, 68, 70, 73, 75, 77, 80, 82, 85, 87, 89, 92, 94, 96, 99, 101, 103, 106, 108, 111, 113, 115, 118, 120, 122, 125, 127, 130, 132, 134, 137, 139 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,2

LINKS

Clark Kimberling, Table of n, a(n) for n = 1..400

EXAMPLE

(A248607(k+1) - A248607(k)) = (1, 2, 1, 2, 1, 2, 1, 2, 1, 2, 1, 2, 1, 2, 1, 2, 1, 2, 2,...), so that A248608 = (1, 3, 5, 7, 9, 11, 13, 15, 17, ..) and A248609 = (2, 4, 6, 8, 10, 12, 14, 16, ...).

MATHEMATICA

z = 300; p[k_] := p[k] = Sum[2^h/((2 h + 1) Binomial[2 h, h]), {h, 0, k}]

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

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

u = Flatten[Table[f[n], {n, 1, z}]]  (* A248607 *)

d = Differences[u]

v = Flatten[Position[d, 1]] (* A248608 *)

w = Flatten[Position[d, 2]] (* A248609 *)

CROSSREFS

Cf. A248607, A248609, A248611.

Sequence in context: A066640 A137507 A061808 * A309325 A192863 A143450

Adjacent sequences:  A248605 A248606 A248607 * A248609 A248610 A248611

KEYWORD

nonn,easy

AUTHOR

Clark Kimberling, Oct 10 2014

STATUS

approved

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Last modified May 7 02:16 EDT 2021. Contains 343636 sequences. (Running on oeis4.)