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 A141640 Additive nonprimes: odd sum of digits is a nonprime. 1
 1, 9, 10, 18, 27, 36, 45, 54, 63, 69, 72, 78, 81, 87, 90, 96, 100, 108, 117, 126, 135, 144, 153, 159, 162, 168, 171, 177, 180, 186, 195, 207, 216, 225, 234, 243, 249, 252, 258, 261, 267, 270, 276, 285, 294, 306, 315, 324, 333, 339, 342, 348, 351, 357, 360, 366 (list; graph; refs; listen; history; text; internal format)
 OFFSET 1,2 COMMENTS A141468(n)=n-th nonprime. LINKS Vincenzo Librandi, Table of n, a(n) for n = 1..1000 EXAMPLE Nonprime (7)=10 is additive nonprime because 1+0=1 (odd) is nonprime (2). Nonprime (12)=18 is additive nonprime because 1+8=9 (odd) is nonprime (6), etc. MATHEMATICA osdnpQ[n_]:=Module[{s=Total[IntegerDigits[n]]}, OddQ[s]&&!PrimeQ[s]]; Select[Range[400], osdnpQ] (* Harvey P. Dale, Aug 04 2013 *) CROSSREFS Cf. A046704, A141468. Sequence in context: A058369 A110939 A260042 * A231504 A298979 A299969 Adjacent sequences: A141637 A141638 A141639 * A141641 A141642 A141643 KEYWORD nonn,base AUTHOR Juri-Stepan Gerasimov, Sep 03 2008 EXTENSIONS 45 and 207 inserted and extended by R. J. Mathar, Sep 05 2008 STATUS approved

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Last modified March 27 12:09 EDT 2023. Contains 361570 sequences. (Running on oeis4.)