This site is supported by donations to The OEIS Foundation.

 Annual appeal: Please make a donation to keep the OEIS running! Over 6000 articles have referenced us, often saying "we discovered this result with the help of the OEIS". Other ways to donate

 Hints (Greetings from The On-Line Encyclopedia of Integer Sequences!)
 A153498 Palindromes formed from concatenation of A147759(n) and the same string A147759(n) but without its initial digit. 3
 1, 111, 10101, 1001001, 101010101, 10110101101, 1010101010101, 101001010100101, 10101010101010101, 1010110101010110101, 101010101010101010101, 10101001010101010010101 (list; graph; refs; listen; history; text; internal format)
 OFFSET 1,2 COMMENTS a(n) is also A153497(n) written in base 2. LINKS FORMULA a(n)=101*a(n-1)-1110*a(n-2)+102010*a(n-3)-111000*a(n-4)+1010000*a(n-5)-1000000*a(n-6). G.f.: x(1+10x+2000x^3-91000*x^4+100000x^5)/((1-100x)(1-x)(1+10x^2)(1+1000x^2)). [From R. J. Mathar, Feb 20 2009] EXAMPLE n ............. a(n) 1 .............. 1 2 ............. 111 3 ............ 10101 4 ........... 1001001 5 .......... 101010101 6 ......... 10110101101 7 ........ 1010101010101 8 ....... 101001010100101 9 ...... 10101010101010101 10 .... 1010110101010110101 11 ... 101010101010101010101 ====================================== Another visualization of the structure ====================================== 1 .............. * 2 ............. /|\ 3 ............ /.|.\ 4 ........... /..|..\ 5 .......... /.*.|.*.\ 6 ......... /./|.|.|\.\ 7 ........ /./.|.|.|.\.\ 8 ....... /./..|.|.|..\.\ 9 ...... /./.*.|.|.|.*.\.\ 10 .... /././|.|.|.|.|\.\.\ 11 ... /././.|.|.|.|.|.\.\.\ CROSSREFS Cf. A135577, A138146, A152576, A152764, A153497, A153499, A153500, A144564. Sequence in context: A265280 A267275 A135577 * A118110 A267608 A244663 Adjacent sequences:  A153495 A153496 A153497 * A153499 A153500 A153501 KEYWORD easy,base,nonn AUTHOR Omar E. Pol, Dec 27 2008, Feb 18 2009 EXTENSIONS More terms from R. J. Mathar, Feb 20 2009 Keyword:base added by Charles R Greathouse IV, Apr 23 2010 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 | More pages
The OEIS Community | Maintained by The OEIS Foundation Inc.