cp's OEIS Frontend

This is a front-end for the Online Encyclopedia of Integer Sequences, made by Christian Perfect. The idea is to provide OEIS entries in non-ancient HTML, and then to think about how they're presented visually. The source code is on GitHub.

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A374957 Decimal expansion of the circumradius of a regular heptagon with unit side length.

Original entry on oeis.org

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

Views

Author

Paolo Xausa, Jul 26 2024

Keywords

Examples

			1.15238243548124325262057511177342755672225094380...
		

Crossrefs

Cf. A374971 (apothem), A374972 (sagitta), A178817 (area).
Cf. circumradius of other polygons with unit side length: A020760 (triangle), A010503 (square), A300074 (pentagon), A285871 (octagon), A375151 (9-gon), A001622 (10-gon), A375190 (11-gon), A188887 (12-gon).

Programs

Formula

Equals csc(Pi/7)/2 = A121598/2.
Equals 1/(2*sin(Pi/7)) = 1/A272487.
Equals A374971/cos(Pi/7) = A374971/A073052.
Largest of the 6 real-valued roots of 7*x^6-14*x^4+7*x^2-1=0. - R. J. Mathar, Aug 29 2025

A375151 Decimal expansion of the circumradius of a regular 9-gon with unit side length.

Original entry on oeis.org

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

Views

Author

Paolo Xausa, Aug 01 2024

Keywords

Examples

			1.46190220008154362611637720668314585193675283...
		

Crossrefs

Cf. A375152 (apothem), A375153 (sagitta), A256853 (area).
Cf. circumradius of other polygons with unit side length: A020760 (triangle), A010503 (square), A300074 (pentagon), A374957 (heptagon), A285871 (octagon), A001622 (10-gon), A375190 (11-gon), A188887 (12-gon)

Programs

Formula

Equals csc(Pi/9)/2 = A121602/2.
Equals 1/(2*sin(Pi/9)) = 1/A272488.
Equals A375152/cos(Pi/9) = A375152/A019879.
Equals A375152 + A375153.
Largest of the 6 real-valued roots of 3*x^6-9*x^4+6*x^2-1=0. - R. J. Mathar, Aug 29 2025

A375190 Decimal expansion of the circumradius of a regular 11-gon with unit side length.

Original entry on oeis.org

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

Views

Author

Paolo Xausa, Aug 04 2024

Keywords

Examples

			1.774732766442111662856831961168975846105376382123...
		

Crossrefs

Cf. A375191 (apothem), A375192 (sagitta), A256854 (area).
Cf. circumradius of other polygons with unit side length: A020760 (triangle), A010503 (square), A300074 (pentagon), A374957 (heptagon), A285871 (octagon), A375151 (9-gon), A001622 (10-gon), A188887 (12-gon).
Cf. A272489.

Programs

Formula

Equals csc(Pi/11)/2.
Equals 1/(2*sin(Pi/11)) = 1/A272489.
Equals A375191/cos(Pi/11).
Equals A375191 + A375192.

A380736 Decimal expansion of the smallest vertex angle, in radians, in a disdyakis dodecahedron face.

Original entry on oeis.org

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

Views

Author

Paolo Xausa, Feb 01 2025

Keywords

Comments

A disdyakis dodecahedron face is a scalene triangle with three acute angles.

Examples

			0.6592691539262158395617269590815416456187802510390...
		

Crossrefs

Cf. A380737 (face medium angle), A380738 (face largest angle).

Programs

  • Mathematica
    First[RealDigits[ArcCos[1/12 + Sqrt[2]/2], 10, 100]]

Formula

Equals arccos(1/12 + sqrt(2)/2) = arccos(1/12 + A010503).
Equals Pi - A380737 - A380738.

A385506 Decimal expansion of the volume of a triaugmented triangular prism with unit edge.

Original entry on oeis.org

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

Views

Author

Paolo Xausa, Jul 01 2025

Keywords

Comments

The triaugmented triangular prism is Johnson solid J_51.

Examples

			1.140119483078766847782705947481317131020537251141...
		

Crossrefs

Cf. A097715 (surface area).

Programs

  • Mathematica
    First[RealDigits[(Sqrt[8] + Sqrt[3])/4, 10, 100]] (* or *)
    First[RealDigits[PolyhedronData["J51", "Volume"], 10, 100]]

Formula

Equals 1/sqrt(2) + sqrt(3)/4 = A010503 + A120011 = (A010466 + A002194)/4.
Equals the largest root of 256*x^4 - 352*x^2 + 25.

A145439 Decimal expansion of Sum_{k>=0} binomial(4*k, 2*k)/2^(6*k).

Original entry on oeis.org

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

Views

Author

R. J. Mathar, Feb 08 2009

Keywords

Examples

			1.11535507165041054076705837455583093794582718446458...
		

References

  • Alexander Apelblat, Tables of Integrals and Series, Harri Deutsch, 1996, 4.1.49.

Crossrefs

Programs

  • Maple
    1/2*(1+1/3*3^(1/2))*2^(1/2);
  • Mathematica
    RealDigits[1/Sqrt[2] + 1/Sqrt[6], 10, 120][[1]] (* Amiram Eldar, May 29 2023 *)
  • PARI
    1/sqrt(6) + 1/sqrt(2) \\ Michel Marcus, Jan 15 2021

Formula

Equals (1+A020760)*A010503.
Equals A020763 + A010503. - Artur Jasinski, Dec 20 2020
The minimal polynomial is 9*x^4 - 12*x^2 + 1. - Joerg Arndt, Sep 20 2023
Equals 2F1(1/4,3/4; 1/2; 1/4). - R. J. Mathar, Aug 02 2024
Equals Product_{k>=1} (1 - (-1)^k/A092259(k)). - Amiram Eldar, Nov 24 2024

Extensions

Typo in definition corrected by R. J. Mathar, Feb 09 2009

A235362 Decimal expansion of the cube root of 2 divided by 2.

Original entry on oeis.org

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

Views

Author

Alonso del Arte, Jan 07 2014

Keywords

Comments

Also reciprocal of the real cubic root of 4 and negated real part of either complex cubic root of 2.

Examples

			0.6299605249474365823836053...
		

Crossrefs

Programs

  • Maple
    Digits := 100 ; evalf(1/2^(2/3)) ; # R. J. Mathar, Jan 16 2023
  • Mathematica
    RealDigits[1/2^(2/3), 10, 128][[1]]
  • PARI
    sqrtn(1/4,3) \\ Charles R Greathouse IV, Apr 14 2014

Formula

2^(1/3)/2 = 1/2^(2/3) = 1/4^(1/3).
(-2^(1/3)/2 + sqrt(-3)/4^(1/3))^3 = 2.
Equals 1/A005480 = A002580 /2 . - Wolfdieter Lang, Jan 02 2023

A377299 Decimal expansion of the volume of a truncated cube with unit edge length.

Original entry on oeis.org

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

Views

Author

Paolo Xausa, Oct 25 2024

Keywords

Examples

			13.599663291074443561074547379645257699991802085...
		

Crossrefs

Cf. A377298 (surface area), A294968 (circumradius), A010503 (midradius - 1), A377296 (Dehn invariant, negated).
Cf. A131594.

Programs

  • Mathematica
    First[RealDigits[7 + 14*Sqrt[2]/3, 10, 100]] (* or *)
    First[RealDigits[PolyhedronData["TruncatedCube", "Volume"], 10, 100]]

Formula

Equals 7 + (14/3)*sqrt(2) = 7 + 14*A131594.

A023115 Signature sequence of 1/sqrt(2) (arrange the numbers i+j*x (i,j >= 1) in increasing order; the sequence of i's is the signature of x).

Original entry on oeis.org

1, 1, 2, 1, 2, 3, 1, 2, 3, 1, 4, 2, 3, 1, 4, 2, 5, 3, 1, 4, 2, 5, 3, 1, 6, 4, 2, 5, 3, 1, 6, 4, 2, 7, 5, 3, 1, 6, 4, 2, 7, 5, 3, 8, 1, 6, 4, 2, 7, 5, 3, 8, 1, 6, 4, 9, 2, 7, 5, 3, 8, 1, 6, 4, 9, 2, 7, 5, 10, 3, 8, 1, 6, 4, 9, 2, 7, 5, 10, 3, 8, 1, 6, 11, 4, 9, 2, 7, 5, 10, 3, 8
Offset: 1

Views

Author

Keywords

References

  • C. Kimberling, "Fractal Sequences and Interspersions", Ars Combinatoria, vol. 45 p 157 1997.

Crossrefs

Cf. A010503.

A041084 Numerators of continued fraction convergents to sqrt(50).

Original entry on oeis.org

7, 99, 1393, 19601, 275807, 3880899, 54608393, 768398401, 10812186007, 152139002499, 2140758220993, 30122754096401, 423859315570607, 5964153172084899, 83922003724759193, 1180872205318713601, 16616132878186749607, 233806732499933208099, 3289910387877251662993
Offset: 0

Views

Author

Keywords

Crossrefs

Programs

  • Mathematica
    Numerator[Convergents[Sqrt[50],30]] (* or *) LinearRecurrence[{14,1},{7,99},30] (* Harvey P. Dale, Aug 18 2013 *)
    CoefficientList[Series[(7 + x)/(1 - 14 x - x^2), {x, 0, 30}], x] (* Vincenzo Librandi, Oct 29 2013 *)

Formula

a(n) = 14*a(n-1)+a(n-2), n>1 ; a(0)=7, a(1)=99 . G.f.: (7+x)/(1-14*x-x^2). - Philippe Deléham, Nov 21 2008

Extensions

More terms from Colin Barker, Nov 04 2013
Previous Showing 41-50 of 80 results. Next