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Search: id:A115981
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| A115981 |
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Counts compositions but not stacks. |
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+0
2
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| 0, 0, 0, 0, 0, 1, 5, 17, 49, 126, 303, 694, 1536, 3312, 7009, 14619, 30164, 61732, 125568, 254246, 513048, 1032696, 2074875, 4163256, 8345605, 19717996, 33473334, 66998380, 134067959, 268233386, 536599508, 1073378850, 2147000209
(list; graph; listen)
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OFFSET
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0,7
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FORMULA
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A115981(n) = A011782(n) - A001523(n)
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EXAMPLE
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a(5) = 1 counting (212}
a(6) = 5 counting {1212, 2112,2121,213,312}
a(7) = 17 counting {11212, 12112,12121, 21211, 21121, 21112, 2122, 2212,
2113, 3112, 2131, 3121, 1213, 1312, 412, 214, 313 }
a(8) = 49 = 128 - 79
a(9) = 126 = 256 - 130
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CROSSREFS
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Cf. A001523, A011782, A115982.
Sequence in context: A011853 A136303 A006457 this_sequence A083091 A082753 A000337
Adjacent sequences: A115978 A115979 A115980 this_sequence A115982 A115983 A115984
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KEYWORD
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easy,nonn,uned
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AUTHOR
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Alford Arnold (Alford1940(AT)aol.com), Feb 12 2006
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EXTENSIONS
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More terms from Brian Kuehn (brk158(AT)psu.edu), Apr 20 2006
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