Let $\Gamma_p : \mathbb{Z}_p \to \mathbb{Z}_p^{\times}$ be the $p$-adic gamma function. I thought that I had successfully calculated $\Gamma_p(1 - 1/4)$, but sage is telling me I'm wrong (this is more than a sign error, which I have probably made along the way). Here is what I've done: Let $p > 2$ be a prime such that $p \equiv 1 \mod 4$, and $q = p^2$. We will assume that all roots of unity lie in $\mathbb{C}_p^{\times}$. Let $\omega_q : \mathbb{F}_q^{\times} \to \mu_{q-1}\subseteq \mathbb{Z}_p[\mu_q]$ be the Teichmuller character and $\zeta$ a primitive $p$-th root of unity. We denote $\chi = \omega_q^{(q-1)/4}$. Let $Tr : \mathbb{F}_q \to \mathbb{F}_p$ and $N : \mathbb{F}_q \to \mathbb{F}_p$ be the trace and norm respectively. For a finite field $F$ and multiplicative character $\psi$ on $F$, the Gauss sum for $\psi$ is defined to be \begin{align*} G(\psi) = \sum_{c \in F} \psi(c) \zeta^{Tr_{F/\mathbb{F}_p}(c)} \end{align*} and the Jacobi sum for $\psi$ is defined \begin{align*} J(\psi) = \sum_{c \in F} \psi(c) \psi(1-c). \end{align*} Let $\pi$ be the maximal prime in $\mathbb{Z}_p(\zeta)$ such that $\pi \equiv 1-\zeta \mod{\pi^2}$. It follows from the Gross-Koblitz formula that \begin{align*} \Gamma_p\left(1 - \frac{1}{4}\right) ^2= -\frac{\pi^{(p-1)/2}G(\chi)}{q}. \end{align*} Also, if $\omega = \omega_q |_{\mathbb{F}_p} : \mathbb{F}_p \to \mu_{p-1}$ and $\psi = \omega^{(p-1)/4}$, then since \begin{align*} \chi(c) = \omega_q^{(p-1)/4}(c^{p+1}) = \omega_q^{(p-1)/4}(N(c)) = \omega^{(p-1)/4}(N(c)) \end{align*} $G(\chi) = G^2(\psi)$ by the Hasse-Davenport lifting relation. Now, $\psi$ is a quartic character on $\mathbb{F}_p$, which means $\psi^2$ a quadratic character. So, from the well known value \begin{align*} G(\psi^2) = \pi^{(p-1)/2} \end{align*} and from the relation $J(\psi) = G^2(\psi)/G(\psi^2)$, we have \begin{align*} G^2(\psi) = \pi^{(p-1)/2} J(\psi). \end{align*} Putting the pieces together, we now have \begin{align*} \Gamma_p\left(1 - \frac{1}{4}\right) ^2= \frac{J(\psi)}{p}. \end{align*} Again, this all seems correct to me, but sage is telling me I'm wrong. I've been looking at this for a while, and I can't seem to figure out where the mistake is. My first guess is that I messed up the Hasse-Davenport part, but I can't quite see how.