A121795 Expansion of -x*(x+1)^2*(x^8-2*x^7+2*x^6-3*x^5+3*x^4+2*x^2-x+1) / (x^12+6*x^6-1).

1, 1, 1, 3, 5, 3, 5, 5, 5, 18, 31, 18, 31, 31, 31, 111, 191, 111, 191, 191, 191, 684, 1177, 684, 1177, 1177, 1177, 4215, 7253, 4215, 7253, 7253, 7253, 25974, 44695, 25974, 44695, 44695, 44695, 160059, 275423, 160059, 275423, 275423, 275423, 986328

Offset

1,4

Links

Table of n, a(n) for n=1..46.

Formula

G.f.: -x*(x+1)^2*(x^8-2*x^7+2*x^6-3*x^5+3*x^4+2*x^2-x+1) / (x^12+6*x^6-1). - Colin Barker, Mar 15 2013

a(n) = +6*a(n-6) +1*a(n-12). - Colin Barker, Mar 15 2013

Mathematica

SL[n_, p_] := Module[{vars = Table[Unique[ a], {n^2}], iters, mat}, iters = Map[{#, 0, p - 1} &, vars]; mat = Partition[vars, n]; Reap[ Do[If[Det[mat, Modulus -> p] == 1, Sow[mat], Continue[]], Evaluate[Sequence @@ iters]]][[2, 1]]] a0 = SL[2, 2]; M[n_] := a0[[1 + Mod[n, Length[a0]]]] v[1] = {1, 1} v[n_] := v[n] = M[n].v[n - 1] a = Table[Floor[v[n][[1]]], {n, 1, 50}]

Crossrefs

Sequence in context: A142972 A020765 A112756 * A253027 A249384 A228446

Adjacent sequences: A121792 A121793 A121794 * A121796 A121797 A121798

Keyword

nonn,easy

Author

Roger L. Bagula, Aug 24 2006

Extensions

New name from Colin Barker, Mar 17 2013

Status

approved