A189732 a(1)=1, a(2)=5, a(n) = a(n-1) + 5*a(n-2).
1, 5, 10, 35, 85, 260, 685, 1985, 5410, 15335, 42385, 119060, 330985, 926285, 2581210, 7212635, 20118685, 56181860, 156775285, 437684585, 1221561010, 3409983935, 9517788985, 26567708660, 74156653585, 206995196885, 577778464810, 1612754449235, 4501646773285
Offset: 1
Links
- Vincenzo Librandi, Table of n, a(n) for n = 1..100
- Silvana Ramaj, New Results on Cyclic Compositions and Multicompositions, Master's Thesis, Georgia Southern Univ., 2021. See p. 33.
- Index entries for linear recurrences with constant coefficients, signature (1, 5).
Crossrefs
Programs
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Mathematica
LinearRecurrence[{1,5},{1,5},40]
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Maxima
a[1]:1$ a[2]:5$ a[n]:=a[n-1]+5*a[n-2]$ makelist(a[n], n, 1, 29); /* Bruno Berselli, May 24 2011 */
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PARI
a(n)=([0,1; 5,1]^(n-1)*[1;5])[1,1] \\ Charles R Greathouse IV, Oct 21 2022
Formula
G.f.: x*(1+4*x)/(1-x-5*x^2). - Bruno Berselli, May 24 2011
a(n+1) = Sum_{k=0..n} A119473(n,k)*4^k. - Philippe Deléham, Oct 05 2012