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

Author

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

Keywords

• base
• nonn

Comments

Pi = 3.14159265358979323846264338327... (see A000796).

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

Examples

			   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 )
		

Links

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

Crossrefs

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

Programs

Mathematica

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