

A256719


Decimal expansion of the location of the near bifurcation cusp in the Zeeman catastrophe machine.


2



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

1,2


COMMENTS

Positive root of 6*x^27*x2, equal to (7+sqrt(97))/12 (Poston 1978).
Applies to the 'classical' Zeeman machine with a disk of diameter 1 and the distance between the pivot and the fixed point equal to 2. With respect to the pivot, the near and far bifurcation cusps are located on opposite side the fixed point. This constant is the near cusp's distance from the pivot.


REFERENCES

T. Poston and I. Stewart, Catastrophe Theory and its Applications, Pitman Publishing Ltd, 1978, Chapter 5, page 76.
E. C. Zeeman, Catastrophe Theory, Scientific American, April 1976, pages 6570, 7583.


LINKS

Stanislav Sykora, Table of n, a(n) for n = 1..2000
D. Cross, Zeeman's Catastrophe Machine in HTML 5
The Nonlinear Dynamics Group at Drexel University, Zeeman's Catastrophe Machine
Wikipedia, Catastrophe theory


FORMULA

Satisfies 3*a*(2*a1)=2*(2*a+1).


EXAMPLE

1.40407148348300872681218428457646870680801135728689701431...


MATHEMATICA

RealDigits[(7 + Sqrt[97])/12, 10, 111][[1]] (* Robert G. Wilson v, Apr 20 2015 *)


PROG

(PARI) a=(7+sqrt(97))/12 \\ Use \p 2020, and keep 2000 digits


CROSSREFS

Cf. A256720 (far bifurcation cusp).
Sequence in context: A035638 A098002 A241658 * A035622 A112919 A019201
Adjacent sequences: A256716 A256717 A256718 * A256720 A256721 A256722


KEYWORD

nonn,cons


AUTHOR

Stanislav Sykora, Apr 09 2015


STATUS

approved



