  We report the Fermi Large Area Telescope detection of gamma-ray (>100
megaelectronvolts) pulsations from pulsar J1823-3021A in the globular cluster
NGC 6624 with high significance (~7 sigma). Its gamma-ray luminosity L_gamma =
(8.4 +/- 1.6) x10^34 ergs per second, is the highest observed for any
millisecond pulsar (MSP) to date, and it accounts for most of the cluster
emission. The non-detection of the cluster in the off-pulse phase implies that
its contains < 32 gamma-ray MSPs, not ~100 as previously estimated. The
gamma-ray luminosity indicates that the unusually large rate of change of its
period is caused by its intrinsic spin-down. This implies that J1823-3021A, has
the largest magnetic field and is the youngest MSP ever detected, and that such
anomalous objects might be forming at rates comparable to those of the more
normal MSPs.
