A152270 - OEIS

A152270

Let f(n)=Floor[Mod[10^k*(7/(4*k + 1) - 6/(4*k + 3) - 1/(4*k + 5)), 3]]; M0 = {{0, 1}, {1, 1/2}}; M = {{0, 2}, {2, 1}}; as Mh=M0.M.(M0+I*f[n]); v[(n)=Mh.v(n-1), then a(n) is the first element of v.

0, 1, -3, -13, 15, -37, 23, -125, -467, -2269, -2269, -12147, -66877, -66877, -66877, -66877, -370963, -2061725, -11464371, 17899313, 99555423, 99555423, -155471765, -864636987, 1350136841, 1350136841, -2108411107, -2108411107

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OFFSET

0,3

LINKS

G. C. Greubel, Table of n, a(n) for n = 0..1000

MATHEMATICA

f[k_] = Floor[Mod[10^k*(7/(4*k + 1) - 6/(4*k + 3) - 1/(4*k + 5)), 3]];

M0 = {{0, 1}, {1, 1/2}}; M = {{0, 2}, {2, 1}};

Mh[n_] := M0.(M.Inverse[f[n]*IdentityMatrix[2] + M0]);

v[0] = {0, 1};

v[n_] := v[n] = Mh[n].v[n - 1]

Table[ -v[n][[1]]/2, {n, 0, 30}]