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Search: id:A057081
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| A057081 |
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Even indexed Chebyshev U-polynomials evaluated at sqrt(11)/2. |
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+0 4
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| 1, 10, 89, 791, 7030, 62479, 555281, 4935050, 43860169, 389806471, 3464398070, 30789776159, 273643587361, 2432002510090, 21614379003449, 192097408520951, 1707262297685110, 15173263270645039, 134852107138120241
(list; graph; listen)
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OFFSET
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0,2
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COMMENT
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This is the m=11 member of the m-family of sequences S(n,m-2)+S(n-1,m-2) = S(2*n,sqrt(m)) (for S(n,x) see Formula). The m=4..10 instances are: A005408, A002878, A001834, A030221, A002315, A033890, and A057080, resp. The m=1..3 (signed) sequences are: A057078, A057077, and A057079, resp.
a(n) = L(n,-9)*(-1)^n, where L is defined as in A108299; see also A070998 for L(n,+9). - Reinhard Zumkeller (reinhard.zumkeller(AT)lhsystems.com), Jun 01 2005
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REFERENCES
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W. Lang, On polynomials related to powers of the generating function of Catalan's numbers, Fib. Quart. 38,5 (2000) 408-419; Eq.(44), rhs, m=11.
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LINKS
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Tanya Khovanova, Recursive Sequences
Index entries for sequences related to Chebyshev polynomials.
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FORMULA
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a(n) = 9*a(n-1)-a(n-2), a(-1)=-1, a(0)=1.
a(n)= S(n, 9)+S(n-1, 9)= S(2*n, sqrt(11)) with S(n, x) := U(n, x/2), Chebyshev polynomials of 2nd kind, A049310. S(n, 9)= A018913(n).
G.f.: (1+x)/(1-9*x+x^2).
Let q(n, x)=sum(i=0, n, x^(n-i)*binomial(2*n-i, i)); then (-1)^n*q(n, -11)=a(n) - Benoit Cloitre (benoit7848c(AT)orange.fr), Nov 10 2002
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CROSSREFS
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Sequence in context: A000826 A031416 A120923 this_sequence A024132 A044261 A065690
Adjacent sequences: A057078 A057079 A057080 this_sequence A057082 A057083 A057084
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KEYWORD
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nonn
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AUTHOR
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Wolfdieter Lang (wolfdieter.lang(AT)physik.uni-karlsruhe.de) Aug 04 2000
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