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%I #17 May 20 2017 19:50:56
%S 6,11,28,37,46,55,120,137,154,171,188,205,222,239,496,529,562,595,628,
%T 661,694,727,760,793,826,859,892,925,958,991,2016,2081,2146,2211,2276,
%U 2341,2406,2471,2536,2601,2666,2731,2796,2861,2926,2991,3056,3121
%N Value of (n,n+1) concatenated in binary representation.
%C a(n) = n * 2^A070939(n+1) + (n+1).
%H Paolo P. Lava, <a href="/A087737/b087737.txt">Table of n, a(n) for n = 1..10000</a>
%e n=12: 12->'1100', 12+1->'1101', a(12)='1100''1101'='11001101'->205.
%p a:= n-> n*(2^(ilog2(n+1)+1)+1)+1:
%p seq(a(n), n=1..50); # _Alois P. Heinz_, May 20 2017
%t Table[FromDigits[Join[IntegerDigits[n,2],IntegerDigits[n+1,2]],2],{n,50}] (* _Harvey P. Dale_, Jan 14 2013 *)
%t Table[n 2^IntegerLength[#, 2] + # &[n + 1], {n, 48}] (* _Michael De Vlieger_, May 20 2017 *)
%o (PARI) a(n) = fromdigits(Vec(concat(binary(n), binary(n+1))), 2); \\ _Michel Marcus_, May 20 2017
%Y Cf. A007088, A001704.
%K nonn,base
%O 1,1
%A _Reinhard Zumkeller_, Oct 01 2003