A140330 - OEIS

%I #10 Jul 21 2017 16:21:52

%S 1,6,14,15,55,63,247,255,511,1023,2047,4095,12287,16383,32767,65535,

%T 196607,262143,983039,1048575,2097151,4194303,8388607,16777215,

%U 33554431,67108863,134217727,268435455,536870911,1073741823,3221225471

%N Smallest nonprime with Hamming weight n (i.e., with exactly n 1's when written in binary).

%C Apart from the first term, identical to A089226. - _R. J. Mathar_, May 31 2008

%F a(n) = MIN{k such that k is in A018252 and A000120(k) = n}.

%e a(10) = 1023 because 1023 base 2 = 1111111111 which has 10 1's and 1023 = 3 * 11 * 31 is nonprime.

%Y Cf. A061712.

%K easy,base,nonn

%O 1,2

%A _Jonathan Vos Post_, May 26 2008

%E More terms from _R. J. Mathar_, May 31 2008