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A219863 Decimal expansion of 1 - 1/e^2. 6
8, 6, 4, 6, 6, 4, 7, 1, 6, 7, 6, 3, 3, 8, 7, 3, 0, 8, 1, 0, 6, 0, 0, 0, 5, 0, 5, 0, 2, 7, 5, 1, 5, 5, 9, 6, 5, 9, 2, 3, 6, 8, 4, 5, 4, 0, 9, 0, 4, 2, 4, 1, 1, 8, 5, 3, 1, 8, 4, 1, 1, 2, 7, 3, 4, 5, 9, 2, 6, 6, 2, 5, 8, 9, 8, 5, 1, 2, 3, 1, 0, 0, 6, 2, 9, 0, 1, 8, 7, 7, 5, 0, 9, 3, 4, 2, 9, 5, 1, 2 (list; constant; graph; refs; listen; history; text; internal format)
OFFSET

0,1

COMMENTS

Consider a substrate (such as polyvinyl alcohol or in forming the polymer of methyl vinyl ketone) in a "1,3 configuration" in which substituents branching off the substrate can irreversibly join with neighboring substituents unless the neighbor is already joined to its other neighbor. Then this constant is the fraction of unjoined substituents on an infinite substrate.

This also applies to reversible reactions when the rate of forward reaction is much faster than that of backward reaction; see Flory p. 1518 footnote 5. This had "satisfactory accord" with his experimental data using methyl vinyl ketone polymer for which the experimentally-obtained percentage was 0.85.

(A 1,k configuration is a substituent branching off a carbon atom, k-2 intermediate carbon atoms, and substituent branching off a carbon atom.)

Solution of the discrete parking problem when infinite lattice randomly filled with 2-length segments. - Philipp O. Tsvetkov, Mar 27 2019

REFERENCES

Pavel L. Krapivsky, Sidney Redner, and Eli Ben-Naim, A Kinetic View of Statistical Physics, Cambridge University Press, 2010.

LINKS

Table of n, a(n) for n=0..99.

Paul J. Flory, Intramolecular reaction between neighboring substituents of vinyl polymers, Journal of the American Chemical Society 61:6 (1939), pp. 1518-1521.

FORMULA

Equals 2*A247847. - Philipp O. Tsvetkov, Mar 27 2019

EXAMPLE

0.8646647167633873081060005...

MATHEMATICA

RealDigits[1 - E^(-2), 10, 105][[1]] (* Alonso del Arte, Dec 04 2012 *)

PROG

(PARI) 1-exp(-2)

CROSSREFS

Cf. A092553, A013301, A247847.

Sequence in context: A261027 A296041 A008569 * A021906 A154187 A011329

Adjacent sequences:  A219860 A219861 A219862 * A219864 A219865 A219866

KEYWORD

nonn,cons

AUTHOR

Charles R Greathouse IV, Nov 30 2012

STATUS

approved

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Last modified October 16 13:51 EDT 2019. Contains 328093 sequences. (Running on oeis4.)