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A201524 Decimal expansion of greatest x satisfying 7*x^2-1=sec(x) and 0<x<pi. 3
1, 5, 0, 3, 2, 6, 2, 1, 5, 2, 1, 3, 1, 4, 9, 3, 0, 9, 9, 9, 1, 9, 0, 7, 9, 9, 0, 7, 5, 2, 0, 0, 8, 3, 0, 8, 2, 9, 0, 8, 3, 4, 3, 1, 7, 1, 5, 6, 2, 7, 8, 2, 9, 3, 8, 3, 2, 1, 0, 3, 3, 2, 1, 4, 8, 8, 7, 2, 7, 4, 9, 7, 2, 3, 3, 7, 5, 1, 4, 2, 4, 9, 8, 0, 0, 9, 9, 4, 8, 7, 2, 9, 9, 6, 6, 2, 0, 5, 6 (list; constant; graph; refs; listen; history; text; internal format)
OFFSET

1,2

COMMENTS

See A201397 for a guide to related sequences.  The Mathematica program includes a graph.

LINKS

Table of n, a(n) for n=1..99.

EXAMPLE

least:  0.557895175779035299832869736313873...

greatest: 1.5032621521314930999190799075200...

MATHEMATICA

a = 7; c = -1;

f[x_] := a*x^2 + c; g[x_] := Sec[x]

Plot[{f[x], g[x]}, {x, 0, Pi/2}, {AxesOrigin -> {0, 0}}]

r = x /. FindRoot[f[x] == g[x], {x, .5, .6}, WorkingPrecision -> 110]

RealDigits[r]   (* A201523 *)

r = x /. FindRoot[f[x] == g[x], {x, 1.5, 1.6}, WorkingPrecision -> 110]

RealDigits[r]   (* A201524 *)

CROSSREFS

Cf. A201397.

Sequence in context: A176867 A229175 A326188 * A230438 A200399 A161485

Adjacent sequences:  A201521 A201522 A201523 * A201525 A201526 A201527

KEYWORD

nonn,cons

AUTHOR

Clark Kimberling, Dec 02 2011

STATUS

approved

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Last modified October 19 04:40 EDT 2019. Contains 328211 sequences. (Running on oeis4.)