A280819 -id:A280819 - cp's OEIS frontend

A280533 Decimal expansion of 14*sin(Pi/14).

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

Offset: 1

Rick L. Shepherd, Jan 04 2017

Decimal expansion of the ratio of the perimeter of a regular 7-gon (heptagon) to its diameter (largest diagonal).

			3.115293075388401660044635902955126632528977962703629374367818222563897248...

G. C. Greubel, Table of n, a(n) for n = 1..10000
Index entries for algebraic numbers, degree 3.

Cf. For other n-gons: A010466 (n=4), 10*A019827 (n=5, 10), A280585 (n=8), A280633 (n=9), A280725 (n=11), A280819 (n=12).

Cf. A232736.

RealDigits[14*Sin[Pi/14], 10, 129][[1]] (* G. C. Greubel, Sep 20 2022 *)

PARI
```
14*sin(Pi/14)
```

numerical_approx(14*sin(pi/14), digits=127) # G. C. Greubel, Sep 20 2022

Equals 14*A232736.

A280725 Decimal expansion of 22*sin(Pi/22).

Original entry on oeis.org

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

Offset: 1

Rick L. Shepherd, Jan 07 2017

The ratio of the perimeter of a regular 11-gon (hendecagon) to its diameter (largest diagonal).

Also least positive root of x^5 - 11x^4 - 484x^3 + 3993x^2 + 43923x - 161051.

			3.130926442012273089763438709560132713403129944771655225197821304298120771...

Index entries for algebraic numbers, degree 5.

Cf. For other n-gons: A010466 (n=4), 10*A019827 (n=5, 10), A280533 (n=7), A280585 (n=8), A280633 (n=9), A280819 (n=12).

evalf(22*sin(Pi/22),100); # Wesley Ivan Hurt, Feb 01 2017

RealDigits[22*Sin[Pi/22], 10, 120][[1]] (* Amiram Eldar, Jun 26 2023 *)

PARI
```
22*sin(Pi/22)
```

A280585 Decimal expansion of 8*sin(Pi/8).

Original entry on oeis.org

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

Offset: 1

Rick L. Shepherd, Jan 05 2017

Decimal expansion of the ratio of the perimeter of a regular 8-gon (octagon) to its diameter (largest diagonal).

			3.061467458920718173827679872243190934090756499885016331470405085020368271...

Index entries for algebraic numbers, degree 4.

Cf. For other n-gons: A010466 (n=4), 10*A019827 (n=5, 10), A280533 (n=7), A280633 (n=9), A280725 (n=11), A280819 (n=12).

Cf. A182168.

evalf(8*sin(Pi/8),100); # Wesley Ivan Hurt, Feb 01 2017

RealDigits[8*Sin[Pi/8], 10, 120][[1]] (* Amiram Eldar, Jun 26 2023 *)

PARI
```
8*sin(Pi/8)
```

Equals 8*A182168.

A280633 Decimal expansion of 18*sin(Pi/18).

Original entry on oeis.org

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

Offset: 1

Rick L. Shepherd, Jan 06 2017

The ratio of the perimeter of a regular 9-gon (nonagon) to its diameter (largest diagonal).

Also least positive root of x^3 - 243x + 729.

			3.125667198004746279330899281847666328006762189313248970252344806377184798...

Index entries for algebraic numbers, degree 3.

Cf. For other n-gons: A010466 (n=4), 10*A019827 (n=5, 10), A280533 (n=7),A280585 (n=8), A280725(n=11), A280819 (n=12).

evalf(18*sin(Pi/18),100); # Wesley Ivan Hurt, Feb 01 2017

RealDigits[18*Sin[Pi/18],10,120][[1]] (* Harvey P. Dale, Dec 02 2018 *)

PARI
```
18*sin(Pi/18)
```

18*A019819.

cp's OEIS Frontend

A280533 Decimal expansion of 14*sin(Pi/14).

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A280725 Decimal expansion of 22*sin(Pi/22).

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A280585 Decimal expansion of 8*sin(Pi/8).

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A280633 Decimal expansion of 18*sin(Pi/18).

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