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Triangle T(n,k) read by rows: T(n,k) is the number of compositions of n where the k-th part is the last occurrence of a smallest part, n>=1, 1<=k<=n.
1

%I #7 Feb 26 2014 08:57:24

%S 1,1,1,2,1,1,2,3,2,1,4,4,4,3,1,5,7,8,7,4,1,8,11,14,14,11,5,1,12,18,23,

%T 27,25,16,6,1,19,27,39,49,51,41,22,7,1,28,44,64,85,98,92,63,29,8,1,45,

%U 69,103,144,180,189,155,92,37,9,1,70,109,166,241,319,366,344,247,129,46,10,1

%N Triangle T(n,k) read by rows: T(n,k) is the number of compositions of n where the k-th part is the last occurrence of a smallest part, n>=1, 1<=k<=n.

%C Column k=1 is A079501.

%C Row sums are A011782.

%H Joerg Arndt, <a href="/A238348/b238348.txt">Table of n, a(n) for n = 1..465</a> (rows 1..30, flattened)

%e Triangle starts:

%e 01: 1,

%e 02: 1, 1,

%e 03: 2, 1, 1,

%e 04: 2, 3, 2, 1,

%e 05: 4, 4, 4, 3, 1,

%e 06: 5, 7, 8, 7, 4, 1,

%e 07: 8, 11, 14, 14, 11, 5, 1,

%e 08: 12, 18, 23, 27, 25, 16, 6, 1,

%e 09: 19, 27, 39, 49, 51, 41, 22, 7, 1,

%e 10: 28, 44, 64, 85, 98, 92, 63, 29, 8, 1,

%e 11: 45, 69, 103, 144, 180, 189, 155, 92, 37, 9, 1,

%e 12: 70, 109, 166, 241, 319, 366, 344, 247, 129, 46, 10, 1,

%e 13: 110, 172, 267, 398, 551, 679, 709, 591, 376, 175, 56, 11, 1,

%e ...

%K nonn,tabl

%O 1,4

%A _Joerg Arndt_ and _Alois P. Heinz_, Feb 25 2014