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

1,1

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.

Links

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

Example

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

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 *)

Crossrefs

Cf. A000796, A002113, A119351.

Cf. A135697, A039954.

Sequence in context: A306140 A317373 A083974 * A360803 A088102 A039954

Adjacent sequences: A135695 A135696 A135697 * A135699 A135700 A135701

Keyword

base,nonn

Author

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

Extensions

More terms from Harvey P. Dale, Oct 06 2011

Status

approved