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A133345
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a(n) = 2*a(n-1) + 14*a(n-2) for n>1, a(0)=1, a(1)=1.
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7
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1, 1, 16, 46, 316, 1276, 6976, 31816, 161296, 768016, 3794176, 18340576, 89799616, 436367296, 2129929216, 10369000576, 50557010176, 246280028416, 1200358199296, 5848636796416, 28502288382976, 138885491915776
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OFFSET
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0,3
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COMMENTS
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Binomial transform of A001024 (powers of 15), with interpolated zeros.
a(n) is the number of compositions of n when there are 1 type of 1 and 15 types of other natural numbers. - Milan Janjic, Aug 13 2010
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LINKS
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FORMULA
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G.f.: (1-x)/(1-2*x-14*x^2).
If p[1]=1, and p[i]=15, (i>1), and if A is Hessenberg matrix of order n defined by: A[i,j]=p[j-i+1], (i<=j), A[i,j]=-1, (i=j+1), and A[i,j]=0 otherwise. Then, for n>=1, a(n)=det A. - Milan Janjic, Apr 29 2010
a(n) = (b*i)^(n-1)*(b*i*ChebyshevU(n, -i/b) - ChebyshevU(n-1, -i/b)), with b = sqrt(14). - G. C. Greubel, Oct 15 2022
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MATHEMATICA
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LinearRecurrence[{2, 14}, {1, 1}, 30] (* Harvey P. Dale, Jan 07 2016 *)
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PROG
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(Magma) [n le 2 select 1 else 2*(Self(n-1) +7*Self(n-2)): n in [1..41]]; // G. C. Greubel, Oct 15 2022
(SageMath)
A133345=BinaryRecurrenceSequence(2, 14, 1, 1)
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CROSSREFS
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KEYWORD
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nonn,easy
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AUTHOR
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STATUS
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approved
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