A135698 Palindromes with odd number of digits formed from the reflected decimal expansion of Pi.

3, 313, 31413, 3141413, 314151413, 31415951413, 3141592951413, 314159262951413, 31415926562951413, 3141592653562951413, 314159265353562951413, 31415926535853562951413, 3141592653589853562951413, 314159265358979853562951413, 31415926535897979853562951413

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 2n - 1.

The first five members of this sequence are in the example of A119351.

Examples

			n ........... a(n)
1 ............ 3
2 ........... 313
3 .......... 31413
4 ......... 3141413
5 ........ 314151413
6 ....... 31415951413
7 ...... 3141592951413
8 ..... 314159262951413
9 .... 31415926562951413
10 .. 3141592653562951413
		

Links

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

Crossrefs

Cf. A000796, A002113, A119351.

Cf. A135697, A039954.

Programs

Mathematica

pinxt[n_]:=With[{pid=RealDigits[Pi,10,20][[1]]},Module[{a=Take[pid,n]}, FromDigits[Join[a,Reverse[Most[a]]]]]]; Table[pinxt[n],{n,1,15}] (* Harvey P. Dale, Oct 06 2011 *)

Extensions

More terms from Harvey P. Dale, Oct 06 2011