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Central diagonal and left half of table A054225 which counts the partitions of n objects of 2 colors.
1

%I #8 Mar 31 2012 13:23:38

%S 1,1,2,2,3,4,5,7,9,7,12,16,11,19,29,31,15,30,47,57,22,45,77,97,109,30,

%T 67,118,162,189,42,97,181,257,323,339,56,139,267,401,522,589,77,195,

%U 392,608,831,975,1043,101,272,560,907,1279,1576,1752,135,373

%N Central diagonal and left half of table A054225 which counts the partitions of n objects of 2 colors.

%C Every diagonal appears in sequence A129306.

%e Table A054225 begins

%e 1

%e 1...1

%e 2...2...2

%e 3...4...4...3

%e 5...7...9...7...5

%e 7..12..16..16..12..7

%e The diagonals in the new table begin

%e 1..1..2..3..5...7...11...15...22...30..42 A000041

%e .....2..4..7..12...19...30...45...67..97 A000070

%e ........9.16..29...47...77..118..181

%e ..........31..57...97..162..257

%e .............109..189..323

%e ..................339

%Y Cf. A108464, A129306.

%K nonn,tabf

%O 0,3

%A _Alford Arnold_, Jul 11 2007

%E More terms from _R. J. Mathar_, Sep 02 2007