A108985 Expansion of (x+1)*(x^3-x^2-x-1)/((1-x)*(x^2+2*x-1)*(x^2+x+1)).
1, 4, 11, 27, 66, 161, 389, 940, 2271, 5483, 13238, 31961, 77161, 186284, 449731, 1085747, 2621226, 6328201, 15277629, 36883460, 89044551, 214972563, 518989678, 1252951921, 3024893521, 7302738964, 17630371451, 42563481867, 102757335186
Offset: 0
Links
- Colin Barker, Table of n, a(n) for n = 0..1000
- Index entries for linear recurrences with constant coefficients, signature (2,1,1,-2,-1).
Programs
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PARI
Vec((1 + x)*(1 + x + x^2 - x^3) / ((1 - x)*(1 + x + x^2)*(1 - 2*x - x^2)) + O(x^30)) \\ Colin Barker, May 06 2019
Formula
a(n) = 2*a(n-1) + a(n-2) + a(n-3) - 2*a(n-4) - a(n-5) for n>4. - Colin Barker, May 06 2019
Comments