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Number of weakly unimodal compositions of n with absolute difference of successive parts <= 1.
2

%I #10 Mar 22 2014 12:09:33

%S 1,1,2,4,6,10,14,21,27,40,52,70,92,124,156,206,264,335,425,539,673,

%T 847,1052,1300,1611,1990,2433,2977,3638,4420,5367,6496,7829,9439,

%U 11341,13590,16270,19425,23135,27525,32697,38745,45844,54168,63875,75247,88493,103892

%N Number of weakly unimodal compositions of n with absolute difference of successive parts <= 1.

%H Alois P. Heinz, <a href="/A238871/b238871.txt">Table of n, a(n) for n = 0..1000</a>

%e The a(8) = 27 such compositions are:

%e 01: [ 1 1 1 1 1 1 1 1 ]

%e 02: [ 1 1 1 1 1 1 2 ]

%e 03: [ 1 1 1 1 1 2 1 ]

%e 04: [ 1 1 1 1 2 1 1 ]

%e 05: [ 1 1 1 1 2 2 ]

%e 06: [ 1 1 1 2 1 1 1 ]

%e 07: [ 1 1 1 2 2 1 ]

%e 08: [ 1 1 1 2 3 ]

%e 09: [ 1 1 2 1 1 1 1 ]

%e 10: [ 1 1 2 2 1 1 ]

%e 11: [ 1 1 2 2 2 ]

%e 12: [ 1 2 1 1 1 1 1 ]

%e 13: [ 1 2 2 1 1 1 ]

%e 14: [ 1 2 2 2 1 ]

%e 15: [ 1 2 2 3 ]

%e 16: [ 1 2 3 2 ]

%e 17: [ 2 1 1 1 1 1 1 ]

%e 18: [ 2 2 1 1 1 1 ]

%e 19: [ 2 2 2 1 1 ]

%e 20: [ 2 2 2 2 ]

%e 21: [ 2 3 2 1 ]

%e 22: [ 2 3 3 ]

%e 23: [ 3 2 1 1 1 ]

%e 24: [ 3 2 2 1 ]

%e 25: [ 3 3 2 ]

%e 26: [ 4 4 ]

%e 27: [ 8 ]

%Y Cf. A001522, A001523, A005169, A034297, A238870, A238872.

%K nonn

%O 0,3

%A _Joerg Arndt_, Mar 21 2014