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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
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
Sequence in context: A020150 A178389 A297304 * A201066 A200931 A044159
KEYWORD
nonn,base
AUTHOR
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

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