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.

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A346999 a(n) is the maximum of x^(n - x), rounded to the nearest integer, for nonnegative real x.

Original entry on oeis.org

1, 1, 1, 2, 4, 10, 27, 83, 281, 1035, 4127, 17656, 80598, 390649, 2001779, 10804600, 61230207, 363291235, 2251035412, 14533496547, 97575061512, 679975389773, 4910327064257, 36688562599092, 283236504667511, 2256366104654141, 18526697776919183, 156616975726597637
Offset: 0

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Author

Hugo Pfoertner, Aug 12 2021

Keywords

Comments

The maximum of f(x) = x^(n-x) occurs at x_m(n) that is the solution of x*(1+log(x)) = n. - Bernard Schott, Oct 03 2021

Examples

			a(0) = 0^0 = 1 by convention.
a(1) = 1, because 1^0 = 1, but any x > 0.34632336... (A333318) would make x^(1-x) > 0.5.
a(2) = 1 because the maximum of f(x) = x^(2-x) occurs at x_m = 1.4547332..., f(x_m) = 1.2267621..., round(f(x_m)) = 1.
a(5) = 10: maximum of f(x) = x^(5-x) occurs at x_m = 2.57141358157..., f(x_m) = 9.91146808..., round(f(x_m)) = 10.
		

Crossrefs

Cf. A003320.

Programs

  • Mathematica
    Table[First[Round[Maximize[x^(n-x),x,Reals]]],{n,0,27}] (* Stefano Spezia, Aug 14 2021 *)
  • PARI
    a346999(limit) = {my(d(n,y)=derivnum(x=y,x^(n-x))); print1(0^0,", "); for(n=1,limit, my(X=solve(x=1,n,d(n,x))); print1(round(X^(n-X)),", "))};
    a346999(27)
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