The On-Line Encyclopedia of Integer Sequences (OEIS)

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A201755

Decimal expansion of the least x satisfying -x^2+4=e^x.
(history; published version)

#5 by Russ Cox at Fri Mar 30 18:58:02 EDT 2012

AUTHOR

_Clark Kimberling (ck6(AT)evansville.edu), _, Dec 05 2011

Discussion

Fri Mar 30

18:58

OEIS Server: https://oeis.org/edit/global/285

#4 by T. D. Noe at Mon Dec 05 21:29:49 EST 2011

STATUS

proposed

approved

#3 by Clark Kimberling at Mon Dec 05 17:59:10 EST 2011

STATUS

editing

proposed

#2 by Clark Kimberling at Mon Dec 05 15:44:33 EST 2011

NAME

allocated for Clark KimberlingDecimal expansion of the least x satisfying -x^2+4=e^x.

DATA

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

OFFSET

1,2

COMMENTS

See A201741 for a guide to related sequences. The Mathematica program includes a graph.

EXAMPLE

least: -1.96463559748886450762265969211097...

greatest: 1.058006401090636308621387446123...

MATHEMATICA

a = -1; b = 0; c = 4;

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

Plot[{f[x], g[x]}, {x, -3, 2}, {AxesOrigin -> {0, 0}}]

r = x /. FindRoot[f[x] == g[x], {x, -2.0, -1.9}, WorkingPrecision -> 110]

RealDigits[r] (* A201755 *)

r = x /. FindRoot[f[x] == g[x], {x, 1.0, 1.1}, WorkingPrecision -> 110]

RealDigits[r] (* A201756 *)

CROSSREFS

Cf. A201741.

KEYWORD

allocated

nonn,cons

AUTHOR

Clark Kimberling (ck6(AT)evansville.edu), Dec 05 2011

STATUS

approved

editing

#1 by Clark Kimberling at Sun Dec 04 16:06:23 EST 2011

NAME

allocated for Clark Kimberling

KEYWORD

allocated

STATUS

approved