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%I #11 Jun 22 2014 02:00:32
%S 1,3,3,4,10,14,11,12,15,16,18,19,15,18,24,31,29,36,49,42,43,56,44,34,
%T 39,42,47,50,51,66,70,72,73,88,71,104,94,97,112,100,101,116,101,77,78,
%U 71,72,87,89,90,99,102,131,105,96,99,107,108,155,129,159,138,131,132,147
%N n-th semiprime minus number of distinct transpositions of digits (zeros and units) in n-th semiprime written in base 2.
%H Vincenzo Librandi, <a href="/A178043/b178043.txt">Table of n, a(n) for n = 1..1000</a>
%F a(n)=s-binomial((A000120(s)+A023416(s)), A000120(s)), where s=semiprime(n).
%t #-Length[Permutations[IntegerDigits[#,2]]]&/@Select[Range[ 2,300], PrimeOmega[ #] == 2&] (* _Harvey P. Dale_, Jun 21 2014 *)
%Y Cf. A001358, A122466.
%K nonn,base
%O 1,2
%A _Juri-Stepan Gerasimov_, May 17 2010
%E More terms from _R. J. Mathar_, May 28 2010
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