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A193537 Decimal expansion of cos(Pi/(1+phi)), where phi is the golden ratio. 0
3, 6, 2, 3, 7, 4, 8, 9, 0, 0, 8, 0, 4, 8, 0, 1, 1, 9, 9, 5, 8, 6, 4, 6, 6, 3, 7, 4, 7, 4, 9, 8, 6, 8, 9, 9, 3, 6, 0, 8, 6, 5, 5, 4, 4, 0, 0, 5, 5, 9, 8, 5, 4, 6, 4, 5, 0, 1, 5, 6, 7, 8, 8, 7, 4, 0, 1, 2, 3, 5, 0, 6, 2, 4, 7, 4, 4, 8, 9, 7, 3, 5, 5, 2, 1, 9, 6, 2, 2, 9, 2, 6, 4, 3, 4, 2, 9, 1, 0 (list; constant; graph; refs; listen; history; text; internal format)
OFFSET

0,1

COMMENTS

cos(Pi/(1+phi)) is the first term in the identity:

cos(Pi/(1+phi))+cos(Pi/phi)=0 which when converted to the exponential form gives: e^(i*Pi/(1+phi))+e^(-i*Pi/(1+phi))+e^(i*Pi/phi)+e^(-i*Pi/phi)=0. In this form it is known as the phi identity because it combines the golden ratio phi with the five fundamental mathematical constants Pi, e, i, 1, 0 that are found in Euler's identity e^(i*Pi) + 1 = 0.

LINKS

Table of n, a(n) for n=0..98.

Frank M. Jackson, Five a day (Letter to Editor), Mathematics Today 50-6 (2014) 321.

FORMULA

c = cos(Pi/(1+phi)) = cos(2*A180014).

EXAMPLE

0.3623748900804801199586466374749868993608655440055985464501567887401235062...

MATHEMATICA

N[Cos[Pi/(1+GoldenRatio)], 100]

PROG

(PARI) cos((3-sqrt(5))*Pi/2) \\ Charles R Greathouse IV, Jul 29 2011

CROSSREFS

Sequence in context: A132120 A021280 A282728 * A319674 A021738 A016614

Adjacent sequences:  A193534 A193535 A193536 * A193538 A193539 A193540

KEYWORD

easy,nonn,cons

AUTHOR

Frank M Jackson, Jul 29 2011

STATUS

approved

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Last modified July 17 14:44 EDT 2019. Contains 325106 sequences. (Running on oeis4.)