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.

A135700 Palindromes formed from the reflected decimal expansion of golden ratio phi.

Original entry on oeis.org

1, 11, 161, 1661, 16161, 161161, 1618161, 16188161, 161808161, 1618008161, 16180308161, 161803308161, 1618033308161, 16180333308161, 161803393308161, 1618033993308161, 16180339893308161, 161803398893308161, 1618033988893308161, 16180339888893308161, 161803398878893308161
Offset: 1

Views

Author

Omar E. Pol, Mar 01 2008, Mar 28 2008

Keywords

Comments

Phi = 1.61803398874989484820458683436... (see A001622).
The number of digits of a(n) is equal to n.

Examples

			n ... Successive digits of a(n)
1 ............ ( 1 )
2 ........... ( 1 1 )
3 .......... ( 1 6 1 )
4 ......... ( 1 6 6 1 )
5 ........ ( 1 6 1 6 1 )
6 ....... ( 1 6 1 1 6 1 )
7 ...... ( 1 6 1 8 1 6 1 )
8 ..... ( 1 6 1 8 8 1 6 1 )
9 .... ( 1 6 1 8 0 8 1 6 1 )
10 .. ( 1 6 1 8 0 0 8 1 6 1 )
		

Crossrefs

Programs

  • Mathematica
    gr=RealDigits[GoldenRatio, 10, 50][[1]]; (* increase for n>100 *)a[n_]:=FromDigits[Join[Take[gr, Ceiling[n/2]], Reverse[Take[gr, n-Ceiling[n/2]]]]]; Array[a, 20] (* James C. McMahon, Apr 29 2025 *)

A138072 Triangle read by rows: row n lists the digits of A135700(n), the palindromic number formed from the reflected decimal expansion of golden ratio phi.

Original entry on oeis.org

1, 1, 1, 1, 6, 1, 1, 6, 6, 1, 1, 6, 1, 6, 1, 1, 6, 1, 1, 6, 1, 1, 6, 1, 8, 1, 6, 1, 1, 6, 1, 8, 8, 1, 6, 1, 1, 6, 1, 8, 0, 8, 1, 6, 1, 1, 6, 1, 8, 0, 0, 8, 1, 6, 1, 1, 6, 1, 8, 0, 3, 0, 8, 1, 6, 1, 1, 6, 1, 8, 0, 3, 3, 0, 8, 1, 6, 1
Offset: 1

Views

Author

Omar E. Pol, Mar 03 2008

Keywords

Comments

Also, successive digits of the numbers A135700(n).

Examples

			Triangle begins:
...... 1
..... 1,1
.... 1,6,1
... 1,6,6,1
.. 1,6,1,6,1
		

Crossrefs

Decimal expansion of phi: A001622. Cf. A135699, A135700, A135696, A138073.

A138116 Triangle read by rows: row n lists the first n digits of the decimal expansion of golden ratio phi.

Original entry on oeis.org

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

Views

Author

Omar E. Pol, Mar 14 2008

Keywords

Comments

Also, successive digits of A011551.

Examples

			Triangle begins:
      1
     1,6
    1,6,1
   1,6,1,8
  1,6,1,8,0
		

Crossrefs

Cf. A001622 (phi), A011551, A138072, A138073, A175834 (polynomial roots).

Programs

  • Mathematica
    s={};Do[AppendTo[s,RealDigits[GoldenRatio,10,n][[1]]],{n,12}];s//Flatten (* James C. McMahon, Jun 05 2025 *)
Showing 1-3 of 3 results.