Frits Beukers (January 1998). "The Diophantine equation Axp+Byq=Czr". Duke Math. J.91 (1): 61–88. doi:10.1215/S0012-7094-98-09105-0. Here: p.61: "the larger [solutions] were found by a computer search performed on Fermat day at Utrecht in November 1993 ... Notice that in each solution an exponent 2 occurs."