cp's OEIS Frontend

This is a front-end for the Online Encyclopedia of Integer Sequences, made by Christian Perfect. The idea is to provide OEIS entries in non-ancient HTML, and then to think about how they're presented visually. The source code is on GitHub.

A201899 Decimal expansion of the greatest x satisfying x^2+3x+2=e^x.

Original entry on oeis.org

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

Views

Author

Clark Kimberling, Dec 06 2011

Keywords

Comments

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

Examples

			least:  -2.1093569955710161272316992470592578841155...
nearest to 0:  -0.608989103010165494835043701926011...
greatest:  2.99223487205393686509331145278388262181...
		

Crossrefs

Programs

  • Mathematica
    a = 1; b = 3; c = 2;
    f[x_] := a*x^2 + b*x + c; g[x_] := E^x
    Plot[{f[x], g[x]}, {x, -3, 3.1}, {AxesOrigin -> {0, 0}}]
    r = x /. FindRoot[f[x] == g[x], {x, -2.2, -2.1}, WorkingPrecision -> 110]
    RealDigits[r]     (* A201897, least *)
    r = x /. FindRoot[f[x] == g[x], {x, -.7, -.6}, WorkingPrecision -> 110]
    RealDigits[r]     (* A201898, nearest 0  *)
    r = x /. FindRoot[f[x] == g[x], {x, 2.9, 3.0}, WorkingPrecision -> 110]
    RealDigits[r]     (* A201899 greatest *)

Extensions

Name corrected by Sean A. Irvine, Jan 12 2025