This site is supported by donations to The OEIS Foundation.

 Please make a donation to keep the OEIS running. We are now in our 55th year. In the past year we added 12000 new sequences and reached 8000 citations (which often say "discovered thanks to the OEIS"). We need to raise money to hire someone to manage submissions, which would reduce the load on our editors and speed up editing. Other ways to donate

 Hints (Greetings from The On-Line Encyclopedia of Integer Sequences!)
 A212952 Decimal expansion of 3*sqrt(3)/16. 0
 3, 2, 4, 7, 5, 9, 5, 2, 6, 4, 1, 9, 1, 6, 4, 4, 9, 2, 5, 3, 6, 3, 9, 6, 1, 8, 9, 0, 3, 2, 3, 5, 1, 0, 6, 8, 8, 0, 1, 7, 7, 5, 9, 8, 5, 0, 8, 9, 4, 4, 6, 3, 6, 7, 7, 6, 0, 4, 6, 3, 8, 0, 8, 6, 4, 7, 2, 3, 7, 4, 4, 0, 6, 7, 0, 4, 0, 0, 0, 0, 6, 9, 5, 2, 7, 1, 4, 9, 1, 0, 0, 1, 6, 9, 8, 4, 1, 0, 7, 9 (list; constant; graph; refs; listen; history; text; internal format)
 OFFSET 0,1 COMMENTS Decimal expansion of constant arising in analysis of classical atom in an expanding universe. Romano calculates, for a classical (Newtonian) hydrogen atom, a bifurcation constant (for the ratio of an atomic characteristic time and a cosmological expansion characteristic time). The expansion of the universe is often viewed as a uniform stretching of space that would affect compact objects such as atoms and stars, as well as the separation of galaxies. One usually hears that bound systems do not take part in the general expansion, but a much more subtle question is whether bound systems expand partially. In this paper, a definitive answer is given for a very simple system: a classical “atom” bound by electrical attraction. With a mathematical description appropriate for undergraduate physics majors, he shows that this bound system either completely follows the cosmological expansion, or, after initial transients, completely ignores it. The result agrees with Bonnor (1999). A quadratic number with denominator 16 and minimal polynomial 256x^2 - 27. - Charles R Greathouse IV, Apr 21 2016 REFERENCES W. B. Bonnor, "Size of a hydrogen atom in the expanding universe"  Class. Quantum Grav. 16(1999), p. 1313. Richard H. Price and Joseph D. Romano, "In an expanding universe, what doesn’t expand?", American Journal of Physics, May 2012, Volume 80, Issue 5, pp. 37. LINKS EXAMPLE 0.3247595264.... PROG (PARI) sqrt(27)/16 \\ Charles R Greathouse IV, Apr 21 2016 CROSSREFS Sequence in context: A054086 A163329 A261147 * A246259 A105025 A129594 Adjacent sequences:  A212949 A212950 A212951 * A212953 A212954 A212955 KEYWORD nonn,easy,cons AUTHOR Jonathan Vos Post, Jun 01 2012 STATUS approved

Lookup | Welcome | Wiki | Register | Music | Plot 2 | Demos | Index | Browse | More | WebCam
Contribute new seq. or comment | Format | Style Sheet | Transforms | Superseeker | Recent
The OEIS Community | Maintained by The OEIS Foundation Inc.

Last modified December 7 00:36 EST 2019. Contains 329812 sequences. (Running on oeis4.)