login
This site is supported by donations to The OEIS Foundation.

 

Logo

Annual Appeal: Today, Nov 11 2014, is the 4th anniversary of the launch of the new OEIS web site. 70,000 sequences have been added in these four years, all edited by volunteers. Please make a donation (tax deductible in the US) to help keep the OEIS running.

Hints
(Greetings from The On-Line Encyclopedia of Integer Sequences!)
A132285 Mirror odd numbers. 4
11, 33, 55, 77, 99, 1001, 1111, 1221, 1331, 1441, 1551, 1661, 1771, 1881, 1991, 3003, 3113, 3223, 3333, 3443, 3553, 3663, 3773, 3883, 3993, 5005, 5115, 5225, 5335, 5445, 5555, 5665, 5775, 5885, 5995, 7007, 7117, 7227, 7337, 7447, 7557, 7667, 7777, 7887 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,1

COMMENTS

Mirror numbers have even number of digits with property that left half digits is mirror of right half digits.

LINKS

Vincenzo Librandi, Table of n, a(n) for n = 1..555

FORMULA

A005408 INTERSECT A001637 INTERSECT A002113. - R. J. Mathar, Aug 22 2007

MATHEMATICA

monQ[n_]:=Module[{len=IntegerLength[n], idn=IntegerDigits[n]}, EvenQ[ len] &&Take[idn, len/2]==Reverse[Take[idn, -len/2]]]; Select[Range[11, 9999, 2], monQ] (* Harvey P. Dale, Apr 18 2014 *)

PROG

(PARI) isok(n) = {if (n % 2 == 0, return (0)); d = digits(n); if (#d % 2 == 1, return (0)); for (i=1, #d/2, if (d[i] != d[#d-i+1], return (0)); ); return (1); } \\ Michel Marcus, Nov 05 2013

CROSSREFS

Cf. A005408, A001637, A002113, A132286, A132288.

Sequence in context: A022671 A029516 A061833 * A249166 A152740 A080859

Adjacent sequences:  A132282 A132283 A132284 * A132286 A132287 A132288

KEYWORD

nonn,base

AUTHOR

Artur Jasinski, Aug 16 2007

STATUS

approved

Lookup | Welcome | Wiki | Register | Music | Plot 2 | Demos | Index | Browse | More | WebCam
Contribute new seq. or comment | Format | Transforms | Superseeker | Recent | More pages
The OEIS Community | Maintained by The OEIS Foundation Inc.

Content is available under The OEIS End-User License Agreement .

Last modified December 18 10:27 EST 2014. Contains 252139 sequences.