This site is supported by donations to The OEIS Foundation.

 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 A296543 A152740 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 | Style Sheet | Transforms | Superseeker | Recent
The OEIS Community | Maintained by The OEIS Foundation Inc.

Last modified October 21 22:47 EDT 2019. Contains 328315 sequences. (Running on oeis4.)