A135699 Palindromes with odd number of digits formed from the reflected decimal expansion of golden ratio phi.

1, 161, 16161, 1618161, 161808161, 16180308161, 1618033308161, 161803393308161, 16180339893308161, 1618033988893308161, 161803398878893308161, 16180339887478893308161

Offset

1,2

Comments

Phi = 1.61803398874989484820458683436... (see A001622).

The number of digits of a(n) is equal to 2n - 1.

Links

G. C. Greubel, Table of n, a(n) for n = 1..250

Example

n ............ a(n)
1 ............. 1
2 ............ 161
3 ........... 16161
4 .......... 1618161
5 ......... 161808161
6 ........ 16180308161
7 ....... 1618033308161
8 ...... 161803393308161
9 ..... 16180339893308161
10 ... 1618033988893308161

Mathematica

With[{ed = RealDigits[(1 + Sqrt[5])/2, 10, 25][[1]]}, Table[FromDigits[Join[Take[ed, n], Reverse[Take[ed, n - 1]]]], {n, 25}]] (* G. C. Greubel, Oct 27 2016 *)

Crossrefs

Cf. A001622, A002113.

Sequence in context: A278205 A197089 A278890 * A092312 A207232 A207225

Adjacent sequences: A135696 A135697 A135698 * A135700 A135701 A135702

Keyword

base,nonn

Author

Omar E. Pol, Mar 01 2008

Status

approved