A174565 Expansion of g.f. (1+3*x)/((1-x)*(1+3*x+4*x^2)).
1, 1, -3, 9, -11, 1, 45, -135, 229, -143, -483, 2025, -4139, 4321, 3597, -28071, 69829, -97199, 12285, 351945, -1104971, 1907137, -1301523, -3723975, 16378021, -34238159, 37202397, 25345449, -224845931, 573156001, -820084275, 167628825, 2777450629, -9002867183
Offset: 0
Links
- Index entries for linear recurrences with constant coefficients, signature (-2, -1, 4).
Programs
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Magma
a087168:=func< n | &+[ Binomial(n+k, 2*k)*(-2)^(n-k): k in [0..n] ] >; [ (1-a087168(n+1))/2: n in [0..35] ];
Formula
a(n) = (1/2)*(1 - A087168(n+1)).
Comments