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 1-4 of 4 results.

A010470 Decimal expansion of square root of 13.

Original entry on oeis.org

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

Views

Author

Keywords

Comments

Continued fraction expansion is 3 followed by {1, 1, 1, 1, 6} repeated. - Harry J. Smith, Jun 02 2009
The convergents to sqrt(13) are given in A041018/A041019. - Wolfdieter Lang, Nov 23 2017
The fundamental algebraic (integer) number in the field Q(sqrt(13)) is (1 + sqrt(13))/2 = A209927. - Wolfdieter Lang, Nov 21 2023

Examples

			3.605551275463989293119221267470495946251296573845246212710453056227166...
		

References

  • Steven R. Finch, Mathematical Constants, Encyclopedia of Mathematics and its Applications, vol. 94, Cambridge University Press, 2003, Section 2.31.4, p. 201.

Crossrefs

Cf. A010122 (continued fraction), A041018/A041019 (convergents), A248242 (Egyptian fraction), A171983 (Beatty sequence).
Cf. A020770 (reciprocal), A209927, A295330, A344069.

Programs

  • Mathematica
    RealDigits[N[Sqrt[13],200]][[1]] (* Vladimir Joseph Stephan Orlovsky, Feb 21 2011 *)
  • PARI
    default(realprecision, 20080); x=sqrt(13); for (n=1, 20000, d=floor(x); x=(x-d)*10; write("b010470.txt", n, " ", d));  \\ Harry J. Smith, Jun 02 2009

A198270 Ceiling(n*sqrt(13)).

Original entry on oeis.org

0, 4, 8, 11, 15, 19, 22, 26, 29, 33, 37, 40, 44, 47, 51, 55, 58, 62, 65, 69, 73, 76, 80, 83, 87, 91, 94, 98, 101, 105, 109, 112, 116, 119, 123, 127, 130, 134, 138, 141, 145, 148, 152, 156, 159, 163, 166, 170, 174, 177, 181, 184, 188, 192
Offset: 0

Views

Author

Vincenzo Librandi, Oct 24 2011

Keywords

Crossrefs

Cf. A171983.

Programs

  • Magma
    [Ceiling(n*Sqrt(13)): n in [0..60]]
  • Mathematica
    With[{c=Sqrt[13]},Ceiling[c*Range[0,60]]] (* Harvey P. Dale, Jul 31 2012 *)

A194116 a(n) = Sum_{j=1..n} floor(j*sqrt(13)); n-th partial sum of Beatty sequence for sqrt(13).

Original entry on oeis.org

3, 10, 20, 34, 52, 73, 98, 126, 158, 194, 233, 276, 322, 372, 426, 483, 544, 608, 676, 748, 823, 902, 984, 1070, 1160, 1253, 1350, 1450, 1554, 1662, 1773, 1888, 2006, 2128, 2254, 2383, 2516, 2653, 2793, 2937, 3084, 3235, 3390, 3548, 3710, 3875
Offset: 1

Views

Author

Clark Kimberling, Aug 16 2011

Keywords

Crossrefs

Cf. A171983 (Beatty sequence for sqrt(13)).

Programs

  • Mathematica
    c[n_] := Sum[Floor[j*Sqrt[13]], {j, 1, n}];
    c = Table[c[n], {n, 1, 90}]
  • Python
    from sympy import integer_nthroot
    def A194116(n): return sum(integer_nthroot(13*j**2,2)[0] for j in range(1,n+1)) # Chai Wah Wu, Mar 17 2021

A198271 Round(n*sqrt(13)).

Original entry on oeis.org

0, 4, 7, 11, 14, 18, 22, 25, 29, 32, 36, 40, 43, 47, 50, 54, 58, 61, 65, 69, 72, 76, 79, 83, 87, 90, 94, 97, 101, 105, 108, 112, 115, 119, 123, 126, 130, 133, 137, 141, 144, 148, 151, 155, 159, 162, 166, 169, 173, 177, 180, 184, 187, 191
Offset: 0

Views

Author

Vincenzo Librandi, Oct 24 2011

Keywords

Crossrefs

Cf. A171983.

Programs

  • Magma
    [Round(n*Sqrt(13)): n in [0..60]]
  • Mathematica
    Round[Sqrt[13]Range[0,60]] (* Harvey P. Dale, Mar 25 2016 *)
Showing 1-4 of 4 results.