A368442 Expansion of e.g.f. exp(-x) / (3 - 2*exp(2*x)).
1, 3, 33, 483, 9537, 235203, 6960993, 240350883, 9484451457, 421047638403, 20768624968353, 1126878096701283, 66701360437693377, 4277150701010241603, 295365044324205535713, 21853794944452689691683, 1724738884402183269207297, 144626802398076537956524803
Offset: 0
Keywords
Programs
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PARI
a_vector(n) = my(v=vector(n+1)); for(i=0, n, v[i+1]=(-1)^i+2*sum(j=1, i, 2^j*binomial(i, j)*v[i-j+1])); v;
Formula
a(n) = (-1)^n + 2 * Sum_{k=1..n} 2^k * binomial(n,k) * a(n-k).