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A178350 Semiprimes with both a prime number of 0's and a prime number of 1's in their binary representations. 3

%I #11 Mar 10 2019 01:43:56

%S 9,10,21,22,25,26,35,38,49,65,87,91,93,94,115,118,121,122,133,134,143,

%T 145,146,155,158,161,185,194,203,205,206,213,214,217,218,319,381,382,

%U 415,445,446,471,478,493,501,502,505,515,517,527,529,535,542,545,551

%N Semiprimes with both a prime number of 0's and a prime number of 1's in their binary representations.

%H Harvey P. Dale, <a href="/A178350/b178350.txt">Table of n, a(n) for n = 1..1000</a>

%e a(1)=9 because 9(written in base 10)=1001 where 2=prime number of 0's and 2=prime number of 1's.

%p A000120 := proc(n) add(d,d=convert(n,base,2)) ; end proc:

%p A080791 := proc(n) dgs :=convert(n,base,2) ; nops(dgs)-A000120(n) ; end proc:

%p for n from 1 to 300 do spr :=A001358(n) ; if isprime( A080791(spr) ) and isprime(A000120(spr)) then printf("%d,",spr) ; end if; end do: # _R. J. Mathar_, Aug 12 2010

%t Select[Range[600],PrimeOmega[#]==2&&AllTrue[{DigitCount[ #,2,0], DigitCount[ #,2,1]},PrimeQ]&] (* The program uses the AllTrue function from Mathematica version 10 *) (* _Harvey P. Dale_, May 25 2016 *)

%Y Cf. A144214, A178064, A178065.

%K nonn,base

%O 1,1

%A _Juri-Stepan Gerasimov_, May 25 2010

%E Corrected (167 removed) by _R. J. Mathar_, Aug 12 2010

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Last modified August 24 23:28 EDT 2024. Contains 375418 sequences. (Running on oeis4.)