A133843 Decimal expansion of the position of the real positive inflection point of Dawson's integral D_+(x).

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

Offset

1,2

Links

Stanislav Sykora, Table of n, a(n) for n = 1..2000

Eric Weisstein's World of Mathematics, Dawson's Integral

Wikipedia, Dawson function

Example

1.5019752682686114988...

Mathematica

RealDigits[x /. FindRoot[-2*Sqrt[Pi]*Erfi[x]*x^2 + 2*E^x^2*x + Sqrt[Pi]*Erfi[x], {x, 1}, WorkingPrecision -> 105]][[1]] (* Jean-François Alcover, Nov 08 2012 *)

Prog

(PARI) Erfi(z) = -I*(1.0-erfc(I*z));
Dawson(z) = 0.5*sqrt(Pi)*exp(-z*z)*Erfi(z); \\ same as F(x)=D_+(x)
D2Dawson(z) = -2.0*(z + (1.0-2.0*z*z)*Dawson(z)); \\ 2nd derivative
x = solve(z=1.0, 2.0, real(D2Dawson(z))) \\ Stanislav Sykora, Sep 17 2014

Crossrefs

Cf. A133841, A133842, A243433, A245262, A247445.

Sequence in context: A164652 A127557 A060524 * A215083 A221308 A241855

Adjacent sequences: A133840 A133841 A133842 * A133844 A133845 A133846

Keyword

nonn,cons

Author

Eric W. Weisstein, Sep 26 2007

Status

approved