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Nonzero elements of table A071675; also counts selected ordered multisets of the values {1,2,3}.
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%I #9 Aug 30 2024 10:19:06

%S 1,1,1,1,1,2,1,3,3,1,2,6,4,1,1,7,10,5,1,6,16,15,6,1,3,19,30,21,7,1,1,

%T 16,45,50,28,8,1,10,51,90,77,36,9,1,4,45,126,161,112,45,10,1,1,30,141,

%U 266,266

%N Nonzero elements of table A071675; also counts selected ordered multisets of the values {1,2,3}.

%e Shift A027907 as indicated and construct a(n) by column.

%e The table begins

%e 1

%e . 1 1 1

%e . . 1 2 3 2 1

%e . . . 1 3 6 7 6 3 1

%e . . . . 1 4 10 16 19 16 10 4 1

%e . . . . . 1 5 15 30 45 51 45 30 15 5 1

%e . . . . . . 1

%e therefore a(19) = 6 and appears in column seven and row three.

%e a(19) counts the ordered multisets {133,313,331,223,232,322}.

%Y Cf. A000073, A027907, A071675, A098925.

%K nonn,tabf

%O 0,6

%A _Alford Arnold_, Oct 23 2004