Ramsey number of a star
= Ramsey number of a star
{c}
For the star $K_{1,t}$,
$$
R(K_{1,t})=
\begin{cases}
2t,&t\text{ odd},\\
2t-1,&t\text{ even}.
\end{cases}
$$
The parity distinction follows from the handshake lemma applied to a hypothetical $(t-1)$-regular colour class on $2t-1$ vertices.