The OEIS mourns the passing of Jim Simons and is grateful to the Simons Foundation for its support of research in many branches of science, including the OEIS.
The OEIS is supported by the many generous donors to the OEIS Foundation.

 Hints (Greetings from The On-Line Encyclopedia of Integer Sequences!)
 A155492 Concatenation of even n and odd n-th nonprime. 0
 21, 69, 1015, 1421, 2839, 3245, 4055, 4257, 4663, 4865, 6081, 6891, 7093, 7295, 86115, 88117, 90119, 92121, 94123, 96125, 102133, 104135, 108141, 110143, 112145, 114147, 118153, 120155 (list; graph; refs; listen; history; text; internal format)
 OFFSET 1,1 LINKS Table of n, a(n) for n=1..28. EXAMPLE Since n=2=even and nonprime(2)=1=odd, concatenate 21 = a(1). Since n=6=even and nonprime(6)=9=odd, concatenate 69 = a(2). Since n=10=even and nonprime(10)=15=odd, concatenate 1015 = a(3), etc. CROSSREFS Cf. A000027, A141468. Sequence in context: A020150 A178389 A297304 * A201066 A200931 A044159 Adjacent sequences: A155489 A155490 A155491 * A155493 A155494 A155495 KEYWORD nonn,base AUTHOR Juri-Stepan Gerasimov, Jan 23 2009 EXTENSIONS Corrected (1421 inserted, 901119 replaced by 90119, 121145 replaced by 112145) R. J. Mathar, May 10 2010 Edited by N. J. A. Sloane, May 15 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 | Recents
The OEIS Community | Maintained by The OEIS Foundation Inc.

Last modified May 21 15:47 EDT 2024. Contains 372738 sequences. (Running on oeis4.)