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 1-3 of 3 results.

A176523 Decimal expansion of (45+3*sqrt(235))/10.

Original entry on oeis.org

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

Views

Author

Klaus Brockhaus, Apr 23 2010

Keywords

Comments

Continued fraction expansion of (45+3*sqrt(235))/10 is A010735.

Examples

			(45+3*sqrt(235))/10 = 9.09891291502676749696...
		

Crossrefs

Cf. A176524 (decimal expansion of sqrt(235)), A010735 (repeat 9, 10).

Programs

  • Mathematica
    RealDigits[(45+3Sqrt[235])/10,10,120][[1]] (* Harvey P. Dale, Aug 27 2011 *)

A176536 Decimal expansion of (15 + sqrt(235))/3.

Original entry on oeis.org

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

Views

Author

Klaus Brockhaus, Apr 24 2010

Keywords

Comments

Continued fraction expansion of (15 + sqrt(235))/3 is A010735 preceded by 10.

Examples

			(15+sqrt(235))/3 = 10.10990323891863055218...
		

Crossrefs

Cf. A176524 (decimal expansion of sqrt(235)), A010735 (repeat 9, 10).

Programs

A207260 Triangle read by rows: T(n,k) = k^2 + (1-(-1)^(n-k))/2.

Original entry on oeis.org

0, 1, 1, 0, 2, 4, 1, 1, 5, 9, 0, 2, 4, 10, 16, 1, 1, 5, 9, 17, 25, 0, 2, 4, 10, 16, 26, 36, 1, 1, 5, 9, 17, 25, 37, 49, 0, 2, 4, 10, 16, 26, 36, 50, 64, 1, 1, 5, 9, 17, 25, 37, 49, 65, 81, 0, 2, 4, 10, 16, 26, 36, 50, 64, 82, 100, 1, 1, 5, 9, 17, 25, 37, 49, 65, 81, 101, 121
Offset: 0

Views

Author

Philippe Deléham, Feb 16 2012

Keywords

Comments

Row sums are A171218(n).

Examples

			Triangle begins:
  0;
  1, 1;
  0, 2, 4;
  1, 1, 5,  9;
  0, 2, 4, 10, 16;
  1, 1, 5,  9, 17, 25;
  0, 2, 4, 10, 16, 26, 36;
  1, 1, 5,  9, 17, 25, 37, 49;
  0, 2, 4, 10, 16, 26, 36, 50, 64;
  1, 1, 5,  9, 17, 25, 37, 49, 65, 81;
  ...
		

Crossrefs

Programs

  • Magma
    /* As triangle */ [[ k^2 + (1-(-1)^(n-k))/2: k in [0..n]]: n in [0.. 15]]; // Vincenzo Librandi, Nov 09 2024
  • Mathematica
    Table[k^2 + (1-(-1)^(n-k))/2, {n, 0, 15}, {k, 0, n}] (* Paolo Xausa, Nov 13 2024 *)

Formula

T(n+k, n) = A002522(n) if k is odd.
T(n+k, n) = n^2 = A000290(n) if k is even.
T(2*n, n) = A137928(n), n>0.
T(2*n+1, n+1) = A080335(n).
T(n,0) = A000035(n).
T(n+1,1) = A000034(n).
T(n+2,2) = A010710(n).
T(n+3,3) = A010735(n).
Sum_{k, 0<=k<=n} T(n,k)*x^k = (-1)^n*A007590(n), A000035(n), A171218(n)
for x = -1, 0, 1 respectively.
G.f.: x*(1 + y - x*y + x*(1 + 2*x)*y^2)/((1 - x^2)*(1 - x*y)^3). - Stefano Spezia, Nov 12 2024
Showing 1-3 of 3 results.