A147776 Decimal expansion of z^(-3)+z^(-2)+z^(-1)+1+z+z^2+z^3, where z = exp(2*Pi*I/23).

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

Offset

1,1

Links

Table of n, a(n) for n=1..99.

Formula

7 - 56*sin(Pi/23)^2 + 112*sin(Pi/23)^4 - 64*sin(Pi/23)^6. - Charles R Greathouse IV, Mar 25 2014

Example

5.9997796702258838608759535245920603550032897005178106973561...

Mathematica

RealDigits[Total[Re[Exp[(2 Pi I)/23]^Range[-3, 3]]], 10, 120][[1]] (* Harvey P. Dale, Jan 02 2022 *)

Prog

(PARI) subst(Pol([-64, 112, -56, 7]), 'x, sin(Pi/23)^2) \\ Charles R Greathouse IV, Mar 25 2014

Crossrefs

Cf. A147777.

Sequence in context: A055199 A147777 A086731 * A020846 A180014 A105643

Adjacent sequences: A147773 A147774 A147775 * A147777 A147778 A147779

Keyword

nonn,cons

Author

N. J. A. Sloane, May 03 2009, based on a posting to the Number Theory List by Nigel Boston, Apr 29 2009

Status

approved