Do first five terms of sequence \left\{\frac{1-(-1)^{n}}{n^{3}}\right\}

For each of the following sequences, write a formula for the general term. Then use the formula to find ${\displaystyle a_{2}0}$
1) $2,7,12,17...$
2) $6,1,-1,9,...$
3) ${\displaystyle a_0=4,d=-0.3}$
4) $a_0=\frac{3}{4},d=-\frac{1}{4}$

${\displaystyle W_n=\frac{3n^{\sqrt{5}}-2n^3+n}{6n^{\sqrt{7}}+4n^3-8}}$, ${\displaystyle Y_n=\frac{6n^5+2n^2-1}{3n^2(2n^3+1)}}$, ${\displaystyle Z_n=1-\sin \left(\frac{2n\pi }{5}\right)}$

Please, continue the two sequences of numbers below and find an equation to each of the sequences: ${\displaystyle n=1,2,3,4,5,6,7}$
Equation ${\displaystyle a_n=2,5,9,14,20,27}$, ${\displaystyle b_n=1,3,12,60,360,2520}$

List the first 10 terms of each of these sequences.
the sequence whose first term is 2, second term is 4, and each succeeding term is the sum of the two preceding terms.

Calculate the Z transform of the sequences
1) ${\displaystyle {(-\frac{1}{5})}^k}$
2) ${\displaystyle \cos k\pi }$
3) ${\displaystyle 3k}$

Tell whether the sequence 12, 4, -4, -12, -20, .... is arithmetic. Explain your reasoning.

Determine whether the given sequence is convergent or divergent
${\displaystyle a_n=\frac{\ln (n+1)}{\sqrt{n}}}$