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.

Showing 1-9 of 9 results.

A110117 a(n) = floor(n * (sqrt(2) + sqrt(3))).

Original entry on oeis.org

3, 6, 9, 12, 15, 18, 22, 25, 28, 31, 34, 37, 40, 44, 47, 50, 53, 56, 59, 62, 66, 69, 72, 75, 78, 81, 84, 88, 91, 94, 97, 100, 103, 106, 110, 113, 116, 119, 122, 125, 128, 132, 135, 138, 141, 144, 147, 151, 154, 157, 160, 163, 166, 169, 173, 176, 179, 182, 185, 188
Offset: 1

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Author

Reinhard Zumkeller, Jul 13 2005

Keywords

Comments

Beatty sequence for sqrt(2)+sqrt(3); complement of A110118;
sqrt(2)+sqrt(3) = 3.14626... = A135611, a weak but interesting Pi approximation.

Crossrefs

Programs

  • Mathematica
    Table[Floor[n*(Sqrt[2] + Sqrt[3])], {n, 1, 50}] (* G. C. Greubel, Jul 02 2017 *)
  • PARI
    for(n=1,50, print1(floor(n*(sqrt(2) + sqrt(3))), ", ")) \\ G. C. Greubel, Jul 02 2017

Extensions

Typo in Link section fixed by Reinhard Zumkeller, Feb 15 2010

A138281 a(n) = floor((sqrt(2) + sqrt(3))^n).

Original entry on oeis.org

1, 3, 9, 31, 97, 308, 969, 3051, 9601, 30210, 95049, 299052, 940897, 2960313, 9313929, 29304086, 92198401, 290080547, 912670089, 2871501385, 9034502497, 28424933309, 89432354889, 281377831710, 885289046401, 2785353383794, 8763458109129, 27572156006234
Offset: 0

Views

Author

Reinhard Zumkeller, Mar 12 2008

Keywords

Crossrefs

Programs

  • Magma
    [Floor((Sqrt(2) + Sqrt(3))^n): n in [0..50]]; // G. C. Greubel, Jan 27 2018
  • Mathematica
    Table[Floor[(Sqrt[2] + Sqrt[3])^n], {n, 0, 50}] (* G. C. Greubel, Jan 27 2018 *)
  • PARI
    for(n=0,50, print1(floor((sqrt(2) + sqrt(3))^n), ", ")) \\ G. C. Greubel, Jan 27 2018
    

Formula

a(2*n) = floor(A001079(n) + A001078(n)*sqrt(6));
(sqrt(2) + sqrt(3))^(2*n) = A001079(n) + A001078(n)*sqrt(6);
a(2*n+1) = floor(A054320(n)*sqrt(2) + A138288(n)*sqrt(3));
(sqrt(2)+sqrt(3))^(2*n+1) = A054320(n)*sqrt(2) + A138288(n)*sqrt(3).

Extensions

Terms a(16) and a(18) corrected, terms a(19) onward added by G. C. Greubel, Jan 27 2018

A377343 Decimal expansion of the surface area of a truncated cuboctahedron (great rhombicuboctahedron) with unit edge length.

Original entry on oeis.org

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

Views

Author

Paolo Xausa, Oct 26 2024

Keywords

Examples

			61.7551724393036681079496207885868453461497255502...
		

Crossrefs

Cf. A377344 (volume), A377345 (circumradius), A377346 (midradius).
Cf. A343199 (analogous for a cuboctahedron).
Cf. A135611.

Programs

  • Mathematica
    First[RealDigits[12*(2 + Sqrt[2] + Sqrt[3]), 10, 100]] (* or *)
    First[RealDigits[PolyhedronData["TruncatedCuboctahedron", "SurfaceArea"], 10, 100]]

Formula

Equals 12*(2 + sqrt(2) + sqrt(3)) = 12*(2 + A135611).

A089078 Continued fraction for sqrt(2) + sqrt(3).

Original entry on oeis.org

3, 6, 1, 5, 7, 1, 1, 4, 1, 38, 43, 1, 3, 2, 1, 1, 1, 1, 2, 4, 1, 4, 5, 1, 5, 1, 7, 22, 2, 5, 1, 1, 2, 1, 1, 31, 2, 1, 1, 3, 1, 44, 1, 89, 1, 8, 5, 2, 5, 1, 1, 4, 2, 8, 1, 17, 1, 4, 3, 4, 3, 2, 1, 1, 4, 2, 1, 9, 1, 15, 13, 1, 39, 20, 2, 152, 3, 2, 4, 1, 30, 1, 3, 1, 2, 1, 2, 16, 3, 24, 1, 9, 1, 172, 3, 1, 1
Offset: 0

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Author

Jeppe Stig Nielsen, Dec 04 2003

Keywords

Comments

This is the most natural example of the fact that the sum of two periodic continued fractions need not have a periodic continued fraction.
a(n) is the numbers of squares removed at stage n of the continued-fraction partitioning of a rectangle of length L and width W satisfying W=L*sqrt(8); see A188640. - Clark Kimberling, Apr 13 2011

Crossrefs

Cf. A135611.

Programs

  • Mathematica
    r = 8^(1/2); t = (r + (4 + r^2)^(1/2))/2; FullSimplify[t]
    N[t, 130]
    RealDigits[N[t, 130]][[1]]
    ContinuedFraction[t, 120]
    ContinuedFraction[Sqrt[2]+Sqrt[3],100] (* Harvey P. Dale, Aug 17 2019 *)
  • PARI
    contfrac(sqrt(2)+sqrt(3)) \\ Michel Marcus, Mar 12 2017

A229194 Integers nearest to (2^((n-3)/2) + 3^((n-3)/2)).

Original entry on oeis.org

1, 1, 1, 2, 3, 5, 8, 13, 21, 35, 58, 97, 163, 275, 466, 793, 1353, 2315, 3969, 6817, 11726, 20195, 34816, 60073, 103724, 179195, 309724, 535537, 926275, 1602515, 2773034, 4799353, 8307516, 14381675, 24899377, 43112257, 74651790, 129271235, 223862687, 387682633, 671402698, 1162785755, 2013837368, 3487832977, 6040770648, 10462450355, 18120829034, 31385253913, 54359521280, 94151567435, 163072632198
Offset: 0

Views

Author

Vladimir Pletser, Sep 15 2013

Keywords

Comments

This sequence illustrates the second law of small numbers because it is a coincidence that the terms for 1 <= n <= 8 are the same as the Fibonacci numbers F(n) (A000045): a(n) = F(n) for 1 <= n <= 8.
Furthermore, the following terms are the sum of two Fibonacci numbers: a(9) = F(9) + F(2), a(10) = F(10) + F(4), a(11) = F(11) + F(6), a(14) = F(14) + F(11); or the algebraic sum of three Fibonacci numbers: a(12) = F(12) + F(8) - F(3), a(13) = F(13) + F(10) - F(7), a(14) = F(14) + F(12) - F(10), a(18) = F(19) - F(13) - F(8), a(19) = F(20) + F(10) - F(4); or the algebraic sum of four Fibonacci numbers: a(15) = F(15) + F(12) + F(9) + F(5), a(16) = F(16) + F(14) - F(6) - F(4), a(17) = F(18) - F(13) - F(9) - F(3), a(18) = F(18) + F(16) + F(14) + F(8), a(19) = F(19) + F(18) + F(10) - F(3).
Note that, for following values of n, a(n) > F(n+1) for n >= 20.
Remark as well that (2^(1/2) + 3^(1/2)) = 3.14626437... ~= Pi (see A135611).

References

  • T. Koshy, Fibonacci and Lucas Numbers with Applications, New York, Wiley-Interscience, 2001
  • I. Stewart, L'univers des nombres, Belin-Pour La Science, Paris 2000.

Crossrefs

Programs

  • Magma
    [Round(2^((n-3)/2) + 3^((n-3)/2)): n in [0..50]]; // Vincenzo Librandi, Sep 20 2013
  • Maple
    seq(round(2^((n-3)/2)+3^((n-3)/2)), n=0..50);
  • Mathematica
    Table[Round[2^((n - 3)/2) + 3^((n - 3)/2)], {n, 0, 50}] (* Vincenzo Librandi, Sep 20 2013 *)

Formula

a(n) = round(2^((n-3)/2) + 3^((n-3)/2)).

A110119 Self-inverse integer permutation induced by Beatty sequences for x and (x+1)/(2*sqrt(2)) with x=sqrt(2)+sqrt(3).

Original entry on oeis.org

3, 6, 1, 9, 12, 2, 15, 18, 4, 22, 25, 5, 28, 31, 7, 34, 37, 8, 40, 44, 47, 10, 50, 53, 11, 56, 59, 13, 62, 66, 14, 69, 72, 16, 75, 78, 17, 81, 84, 19, 88, 91, 94, 20, 97, 100, 21, 103, 106, 23, 110, 113, 24, 116, 119, 26, 122, 125, 27, 128, 132, 29, 135, 138, 141, 30, 144
Offset: 1

Views

Author

Reinhard Zumkeller, Jul 13 2005

Keywords

Crossrefs

Cf. A135611 (sqrt(2)+sqrt(3)).

Formula

a(A110117(n)) = A110118(n) and a(A110118(n)) = A110117(n).

A135798 Decimal expansion of sqrt(2) + sqrt(3) - Pi.

Original entry on oeis.org

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

Views

Author

M. F. Hasler, Mar 06 2008

Keywords

Examples

			0.0046717163521791038664916824360675613153077298122228802575...
		

Crossrefs

Programs

  • Maple
    Digits:=100: evalf(sqrt(2)+sqrt(3)-Pi); # Wesley Ivan Hurt, Jan 24 2017
  • Mathematica
    Join[{0,0},RealDigits[Sqrt[2] + Sqrt[3] - Pi, 10, 100][[1]]] (* G. C. Greubel, Nov 09 2016 *)

A297701 Decimal expansion of 1 + sqrt(2) + sqrt(3).

Original entry on oeis.org

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

Views

Author

Alonso del Arte, Jan 03 2018

Keywords

Comments

This is an algebraic integer of degree 4, with minimal polynomial x^4 - 4*x^3 - 4*x^2 + 16*x - 8.

Examples

			  1.0000000000000000000000000000...
+ 1.4142135623730950488016887242...
+ 1.7320508075688772935274463415...
= 4.1462643699419723423291350657...
		

Crossrefs

Essentially the same as A135611. Cf. A002193, A002194, A014176, A165663, A188582.

Programs

  • Magma
    SetDefaultRealField(RealField(100)); 1 + Sqrt(2) + Sqrt(3); // G. C. Greubel, Nov 20 2018
    
  • Mathematica
    RealDigits[1 + Sqrt[2] + Sqrt[3], 10, 100][[1]]
  • PARI
    1+sqrt(2)+sqrt(3) \\ Felix Fröhlich, Jan 06 2018
    
  • Sage
    numerical_approx(1+sqrt(2)+sqrt(3), digits=100) # G. C. Greubel, Nov 20 2018

Formula

1 + sqrt(2) + sqrt(3) = 1 + sqrt(5 + 2 sqrt(6)).

Extensions

Terms a(52) onward corrected by G. C. Greubel, Nov 20 2018

A340616 Decimal expansion of sqrt(3)-sqrt(2).

Original entry on oeis.org

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

Views

Author

R. J. Mathar, Jan 14 2021

Keywords

Comments

From Bernard Schott, Jan 16 2021: (Start)
Equals the smallest positive root of x^4 - 10*x^2 + 1 (minimal polynomial).
An approximation to 1/Pi (see corresponding comment in A135611). (End)

Examples

			0.317837245195782244725...
		

Crossrefs

Cf. A002193 (sqrt(2)), A002194 (sqrt(3)), A135611 (sqrt(2) + sqrt(3)), A246723 (5-2*sqrt(6)).
Cf. A172264 (Beatty sequence).

Programs

  • Maple
    sqrt(3)-sqrt(2) ; evalf(%) ;
  • Mathematica
    RealDigits[Sqrt[3] - Sqrt[2], 10, 100][[1]] (* Wesley Ivan Hurt, Jan 14 2021 *)
  • PARI
    sqrt(3)-sqrt(2) \\ Michel Marcus, Jan 15 2021

Formula

Equals A002194 - A002193.
Equals A135611 - A010466.
Equals 1/A135611. - Bernard Schott, Jan 15 2021
Equals sqrt(A246723). - Kevin Ryde, Jan 15 2021
Showing 1-9 of 9 results.