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Search: id:A156017
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| A156017 |
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Schroeder paths with two rise colours and two level colours |
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+0
1
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| 1, 4, 24, 176, 1440, 12608, 115584, 1095424, 10646016, 105522176, 1062623232, 10840977408, 111811534848, 1163909087232, 12212421230592, 129027376349184, 1371482141884416, 14656212306231296, 157369985643577344
(list; graph; listen)
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OFFSET
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0,2
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COMMENT
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G.f.: (1-2x-sqrt(1-12x+4x^2))/(4x);
G.f.: 1/(1-2x-2x/(1-2x-2x/(1-2x-2x/(1-... (continued fraction);
a(n)=2^n*sum{k=0..n, C(n+k,2k)*A000108(k)}=2^n*A006318(n).
Hankel transform is 8^C(n+1,2). [From Philippe DELEHAM (kolotoko(AT)wanadoo.fr), Feb 04 2009]
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CROSSREFS
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Sequence in context: A052685 A032349 A103334 this_sequence A000309 A112914 A007846
Adjacent sequences: A156014 A156015 A156016 this_sequence A156018 A156019 A156020
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KEYWORD
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easy,nonn
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AUTHOR
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Paul Barry (pbarry(AT)wit.ie), Feb 01 2009
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