|
%I #4 Aug 24 2012 10:59:35
%S 4,6,9,10,14,15,21,25,26,49,51,57,58,62,65,69,74,77,106,111,115,118,
%T 119,121,122,123,129,133,134,155,158,159,161,166,169,177,178,386,393,
%U 394,395,398,403,407,411,413,437,445,446,447,451,453,458,489,493,497
%N Semiprimes (A001358) which are the sum of distinct double factorials (A006882).
%C Double factorials 0!! and 1!! are not considered distinct. Note that double factorial (n!!) is different from (n!)!.
%e 384 = 2*19 = 8!!+2!!.
%t Union[Select[Total/@Subsets[Range[10]!!,10],PrimeOmega[#]==2&]] (* _Harvey P. Dale_, Aug 24 2012 *)
%Y Cf. A006882, A001358, A115651, A115652, A115653.
%K nonn
%O 1,1
%A _Giovanni Resta_, Jan 28 2006
|
