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a(n) = the number of runs (those of 0 and of 1 considered together) in the binary representation of A175020(n).
5

%I #10 Sep 03 2017 21:30:43

%S 1,2,1,2,3,1,2,3,4,2,1,2,3,4,3,5,2,1,2,3,4,3,4,5,6,2,3,2,1,2,3,4,3,4,

%T 5,3,5,6,4,7,2,3,2,1,2,3,4,3,4,5,3,4,5,6,4,6,5,7,8,2,3,3,4,2,2,1,2,3,

%U 4,3,4,5,3,4,5,6,4,3,5,6,5,7,4,6,7,8,5,9,2,3,3,4,2,3,2,1,2,3,4,3,4,5,3,4,5

%N a(n) = the number of runs (those of 0 and of 1 considered together) in the binary representation of A175020(n).

%C a(n) gives the number of terms in row n of irregular tables A175023 and A175024.

%H Michael De Vlieger, <a href="/A175022/b175022.txt">Table of n, a(n) for n = 1..10000</a>

%t With[{s = Array[Sort@ Map[Length, Split@ IntegerDigits[#, 2]] &, 265]}, Map[Length@ Split@ IntegerDigits[#, 2] &, Values[PositionIndex@ s][[All, 1]] ]] (* _Michael De Vlieger_, Sep 03 2017 *)

%Y Cf. A175020, A175023, A175024, A175025.

%K base,nonn

%O 1,2

%A _Leroy Quet_, Nov 03 2009

%E Extended by _Ray Chandler_, Mar 11 2010