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Search: id:A119020
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| A119020 |
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Eigenvector of triangle A055151 of Motzkin polynomial coefficients, where A055151(n,k) = n!/((n-2k)!*k!*(k+1)!) for 0<=k<=[n/2], n>=0. |
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+0
4
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| 1, 1, 2, 4, 11, 31, 96, 302, 1023, 3607, 13318, 50348, 195361, 772565, 3112630, 12715692, 52648847, 220705119, 937145214, 4028239116, 17522172021, 77071709841, 342583183572, 1537550150766, 6961838925069, 31774593686661
(list; graph; listen)
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OFFSET
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0,3
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COMMENT
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Binomial transform is A119021. Inverse binomial transform is A119022.
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FORMULA
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Eigenvector: a(n) = Sum_{k=0..[n/2]} n!/((n-2k)!*k!*(k+1)!)*a(k), for n>=0, with a(0)=1. G.f. satisfies: A(x) = A(-x/(1-2*x))/(1-2*x)); i.e., 2nd inverse binomial transform equals A(-x). G.f. satisfies: A(x/(1-x))/(1-x)) = A(-x/(1-3*x))/(1-3*x). G.f. of inverse binomial transform: A(x/(1+x))/(1+x)) = B(x^2) where [x^n] B(x) = a(n)*C(2*n,n)/(n+1) = a(n)*A000108(n) and A000108=Catalan.
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EXAMPLE
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A(x) = 1 + x + 2*x^2 + 4*x^3 + 11*x^4 + 31*x^5 + 96*x^6 +...
A(x/(1+x))/(1+x) = 1 + x^2 + 2*2*x^4 + 4*5*x^6 + 11*14*x^8 +...
+ a(n)*A000108(n)*x^(2n) +...
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PROGRAM
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(PARI) {a(n)=if(n==0, 1, sum(k=0, n\2, n!/((n-2*k)!*k!*(k+1)!)*a(k)))}
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CROSSREFS
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Cf. A055151 (Motzkin polynomials), A119021 (binomial), A119022 (inverse binomial).
Sequence in context: A148163 A039300 A118974 this_sequence A073191 A148164 A148165
Adjacent sequences: A119017 A119018 A119019 this_sequence A119021 A119022 A119023
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KEYWORD
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nonn
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AUTHOR
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Paul D. Hanna (pauldhanna(AT)juno.com), May 09 2006
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