The sequence (xn)n∈N is defined by x_1\equal{}2, x_2\equal{}3, and
x_{2m\plus{}1}\equal{}x_{2m}\plus{}x_{2m\minus{}1} for m≥1;
x_{2m}\equal{}x_{2m\minus{}1}\plus{}2x_{2m\minus{}2} for m≥2.
Determine xn as a function of n. functionnumber theory unsolvednumber theory