The OEIS is supported by the many generous donors to the OEIS Foundation.

 Hints (Greetings from The On-Line Encyclopedia of Integer Sequences!)
 A154513 The prime(n)-th digit of the concatenated composites. 2
 6, 8, 1, 1, 1, 1, 2, 2, 2, 2, 2, 3, 3, 3, 3, 4, 4, 4, 5, 5, 5, 6, 6, 6, 7, 7, 7, 7, 8, 8, 9, 9, 9, 9, 1, 4, 6, 0, 1, 1, 1, 7, 1, 1, 1, 3, 8, 3, 1, 5, 1, 1, 1, 1, 1, 1, 1, 3, 5, 1, 8, 1, 8, 1, 0, 1, 7, 0, 1, 5, 1, 1, 2, 5, 8, 2, 2, 5, 2, 9, 2, 4, 2, 8, 0, 2, 2, 8, 2, 1, 2, 2, 2, 2, 6, 2, 2, 2, 5, 2, 5, 2, 2, 2, 5 (list; graph; refs; listen; history; text; internal format)
 OFFSET 1,1 COMMENTS The concatenated composites are A129808, the initial 1 removed. LINKS Table of n, a(n) for n=1..105. FORMULA a(n) = A129808(prime(n)+1). MAPLE a129808 := [1 ] : for n from 4 to 400 do if not isprime(n) then a129808 := [op(a129808), op(ListTools[Reverse](convert(n, base, 10))) ] ; fi; od: for n from 1 do p := ithprime(n) ; printf("%d, ", op(p+1, a129808) ) ; od: # R. J. Mathar, Aug 03 2009 MATHEMATICA nn=700; With[{c=Flatten[IntegerDigits/@Complement[Range[4, nn], Prime[Range[ PrimePi[nn]]]]]}, Flatten[Table[Take[c, {n, n}], {n, Prime[Range[ PrimePi[ nn]]]}]]] (* Harvey P. Dale, Nov 22 2013 *) CROSSREFS Cf. A000040, A002808, A154513, A154520. Sequence in context: A083727 A111838 A197479 * A348435 A239804 A195716 Adjacent sequences: A154510 A154511 A154512 * A154514 A154515 A154516 KEYWORD nonn,base AUTHOR Juri-Stepan Gerasimov, Jan 11 2009 EXTENSIONS Edited and corrected by R. J. Mathar, Aug 03 2009 STATUS approved

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

Last modified September 7 20:21 EDT 2024. Contains 375749 sequences. (Running on oeis4.)