A196605 - OEIS

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A196605

Decimal expansion of the least x>0 satisfying sec(x)=4x.

2, 5, 8, 5, 9, 8, 5, 8, 2, 2, 5, 4, 1, 8, 9, 4, 9, 0, 3, 0, 4, 4, 8, 2, 6, 1, 9, 5, 6, 1, 5, 2, 0, 2, 8, 1, 3, 3, 8, 5, 5, 2, 9, 6, 5, 3, 1, 6, 8, 2, 5, 7, 5, 3, 4, 3, 8, 8, 1, 7, 2, 8, 7, 4, 3, 7, 7, 4, 1, 3, 3, 0, 4, 9, 3, 9, 2, 6, 1, 8, 4, 4, 6, 4, 5, 3, 3, 9, 0, 5, 0, 8, 1, 5, 9, 4, 0, 9, 0, 4

(list; constant; graph; refs; listen; history; text; internal format)

OFFSET

0,1

LINKS

Table of n, a(n) for n=0..99.

EXAMPLE

x=0.25859858225418949030448261956152028133855...

MATHEMATICA

Plot[{1/x, Cos[x], 2 Cos[x], 3*Cos[x], 4 Cos[x]}, {x, 0, 2 Pi}]

t = x /. FindRoot[1/x == Cos[x], {x, .1, 5}, WorkingPrecision -> 100]

RealDigits[t] (* A133868 *)

t = x /. FindRoot[1/x == 2 Cos[x], {x, .5, .7}, WorkingPrecision -> 100]