A135697 Palindromes formed from the reflected decimal expansion of Pi.

3, 33, 313, 3113, 31413, 314413, 3141413, 31411413, 314151413, 3141551413, 31415951413, 314159951413, 3141592951413, 31415922951413, 314159262951413, 3141592662951413, 31415926562951413, 314159265562951413, 3141592653562951413, 31415926533562951413, 314159265353562951413

Offset

1,1

Comments

Pi = 3.14159265358979323846264338327... (see A000796).

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

Links

Paolo Xausa, Table of n, a(n) for n = 1..900

Example

   n        Digits of a(n)
   1             ( 3 )
   2            ( 3 3 )
   3           ( 3 1 3 )
   4          ( 3 1 1 3 )
   5         ( 3 1 4 1 3 )
   6        ( 3 1 4 4 1 3 )
   7       ( 3 1 4 1 4 1 3 )
   8      ( 3 1 4 1 1 4 1 3 )
   9     ( 3 1 4 1 5 1 4 1 3 )
  10    ( 3 1 4 1 5 5 1 4 1 3 )

Mathematica

Table[FromDigits[Join[#[[;; Floor[n/2]]], #[[Ceiling[n/2] ;; 1 ;; -1]]]], {n, Length[#]}] & [First[RealDigits[Pi, 10, 25]]] (* Paolo Xausa, Dec 09 2024 *)

Crossrefs

Cf. A000796, A002113, A039954, A138070, A138071.

Sequence in context: A274264 A107127 A207323 * A226508 A097486 A121515

Adjacent sequences: A135694 A135695 A135696 * A135698 A135699 A135700

Keyword

base,nonn

Author

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

Status

approved