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 A140330 Smallest nonprime with Hamming weight n (i.e., with exactly n 1's when written in binary). 0
 1, 6, 14, 15, 55, 63, 247, 255, 511, 1023, 2047, 4095, 12287, 16383, 32767, 65535, 196607, 262143, 983039, 1048575, 2097151, 4194303, 8388607, 16777215, 33554431, 67108863, 134217727, 268435455, 536870911, 1073741823, 3221225471 (list; graph; refs; listen; history; text; internal format)
 OFFSET 1,2 COMMENTS Apart from the first term, identical to A089226. - R. J. Mathar, May 31 2008 LINKS FORMULA a(n) = MIN{k such that k is in A018252 and A000120(k) = n}. EXAMPLE a(10) = 1023 because 1023 base 2 = 1111111111 which has 10 1's and 1023 = 3 * 11 * 31 is nonprime. CROSSREFS Cf. A061712. Sequence in context: A218005 A063600 A116926 * A242832 A114634 A088017 Adjacent sequences:  A140327 A140328 A140329 * A140331 A140332 A140333 KEYWORD easy,base,nonn AUTHOR Jonathan Vos Post, May 26 2008 EXTENSIONS More terms from R. J. Mathar, May 31 2008 STATUS approved

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Last modified May 28 17:37 EDT 2020. Contains 334684 sequences. (Running on oeis4.)