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A275487 Number of weird numbers (A006037) less than 2^n. 1

%I

%S 0,0,0,0,0,0,0,1,1,1,2,2,3,6,25,66,134,266,505,952,1850,3515,6643,

%T 12920,26893,55786,114992,234719,473299,946406,1884728,3754316,

%U 7467998,14845968

%N Number of weird numbers (A006037) less than 2^n.

%C It is known that the density of weird numbers is positive, but smaller than 0.0101. The three smallest weird numbers are 70, 836 and 4030, therefore a(n) = 0 for n < 7; a(n) = 1 for 7 <= n < 10, and a(n) = 2 for 10 <= n < 12.

%o (PARI) print1(s=0);for(k=0,30,print1(","s+=sum(n=1<<k,2<<k,is_A006037(2*n))))

%Y Cf. A006037.

%K nonn

%O 0,11

%A _M. F. Hasler_, Jul 30 2016

%E a(25)-a(33) from _Amiram Eldar_, Mar 17 2019

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Last modified October 13 20:38 EDT 2019. Contains 327981 sequences. (Running on oeis4.)