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v[1] = 1; v[2] = 3; v[3] = 9; for(n = 3, N, my(i = n + 1); v[i] = (1 + 4*x)*v[i - 3] + 3*v[i - 1]); v};\nrow(n, p) = {my(c = Vecrev(p)); c};\nT(N) = {my(v = P(N)); concat(vector(#v, i, row(i - 1, v[i])))};\nT(9)","reading":{"first_row":0,"offset":0,"reversed":false,"trim_zeros":"none","regular_triangle":false}}],"derivation":{"root":"n-0d55e0bb3c384646","steps":["x \u21a6 (1/27)x","basis A013611"],"edges":["e-b8d37b5fe37403cf","e-5c9cfcdf7ca38f64"],"text":"A102547 \u2192 x \u21a6 (1/27)x \u2192 basis A013611"},"headline":"A102547 \u2192 x \u21a6 (1/27)x \u2192 basis A013611","chain":null}