A158619 - OEIS

%I #10 Feb 03 2019 18:19:28

%S 11101,101111,10111101,1000110011,1110111111,101001101011,

%T 111011111101,10001111001001,11001011100111,11010111101101,

%U 1000100110001011,1001010110010111,1011001110110101,1011111111000001,1100010111000111

%N Twin prime pairs concatenated in binary representation.

%C Binary analog of A095958.

%F a(n) = A007088(A001359(n)) CONCATENATE A007088(A006512(n)) = A007088(A001359(n)) CONCATENATE A007088(A001359(n)+2).

%e a(1) = 11101 because 11_2 = lower of first twin prime pair = 3, and 101_2 = higher of first twin prime pair = 5.

%p A001359 := proc(n) option remember ; if n = 1 then 3; else a := nextprime(procname(n-1)) ; while not isprime(a+2) do a := nextprime(a) ; od: RETURN(a) ; fi: end: A006512 := proc(n) A001359(n)+2 ; end: A007088 := proc(n) bdgs := convert(n,base,2) ; add( op(i,bdgs)*10^(i-1),i=1..nops(bdgs)) ; end: cat2 := proc(a,b) bdgs := max(1, 1+ilog10(b)) ; a*10^bdgs+b ; end: A158619 := proc(n) cat2(A007088(A001359(n)),A007088(A006512(n))) ; end: seq(A158619(n),n=1..30) ; # _R. J. Mathar_, Apr 16 2009

%Y Cf. A001359, A006512, A007088, A045533, A095958.

%K base,easy,nonn

%O 1,1

%A _Jonathan Vos Post_, Mar 22 2009

%E More terms from _R. J. Mathar_, Apr 16 2009