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Search: id:A115190
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| A115190 |
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Fourth diagonal (M=4) of triangle A115154 (called Y(3,1)). |
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+0
1
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| 1, 121, 1762, 20989, 235543, 2588641, 28259704, 308277688, 3369314986, 36937817182, 406378312834, 4487124168115, 49722977591155, 552884158181785, 6167643983348920, 69012419067802540, 774413615153430670
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OFFSET
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0,2
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FORMULA
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a(n)= A115154(n+3,n+1), n>=0.
Recurrence: a(n)= b(n) - 9*(b(n-1)-b(n-2)), with b(n):=A064063(n+4), n>=0.
G.f.: ((-3+18*x+2*x^3) + 3*(1-9*x+9*x^2)*c(3*x))/((2+x)*x^3), with the o.g.f. c(x) of A000108 (Catalan).
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EXAMPLE
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a(0)= 1 = 190 - 9*(25-4); a(2) = 1762 = 14506 - 9*(1606-190).
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CROSSREFS
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Sequence in context: A036308 A066444 A137434 this_sequence A014758 A069600 A018849
Adjacent sequences: A115187 A115188 A115189 this_sequence A115191 A115192 A115193
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KEYWORD
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nonn,easy
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AUTHOR
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Wolfdieter Lang (wolfdieter.lang_AT_physik_DOT_uni-karlsruhe_DOT_de), Feb 23 2006
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