A135696 Palindromes with odd number of digits formed from the reflected decimal expansion of e.

2, 272, 27172, 2718172, 271828172, 27182828172, 2718281828172, 271828181828172, 27182818281828172, 2718281828281828172, 271828182848281828172, 27182818284548281828172, 2718281828459548281828172, 271828182845909548281828172, 27182818284590409548281828172

Offset: 1

Author

Omar E. Pol, Mar 01 2008, corrected Mar 02 2008

Keywords

• base
• nonn

Comments

e = 2.71828182845904523536028747135... (see A001113).

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

Examples

			n ............ a(n)
1 ............. 2
2 ............ 272
3 ........... 27172
4 .......... 2718172
5 ......... 271828172
6 ........ 27182828172
7 ....... 2718281828172
8 ...... 271828181828172
9 ..... 27182818281828172
10 ... 2718281828281828172
		

Links

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

Crossrefs

Cf. A001113, A002113.

Programs

Mathematica

nn=20;With[{ed=RealDigits[E,10,nn][[1]]},Table[FromDigits[Join[Take[ ed,n], Reverse[Take[ed,n-1]]]],{n,nn}]] (* Harvey P. Dale, Sep 10 2012 *)

Extensions

More terms from Harvey P. Dale, Sep 10 2012