1,1

Some of the larger entries may only correspond to probable primes.

f[n_] := n!/10^Sum[Floor[n/5^k], {k, 1, Log[10, n] + 1}]; Do[ If[ PrimeQ[ FromDigits[ Reverse[ IntegerDigits[ f[n]]]] - 1], Print[n]], {n, 1, 800}]

Cf. A078305, A004154.

Sequence in context: A002986 A090660 A000208 this_sequence A101716 A109771 A052626

Adjacent sequences: A079151 A079152 A079153 this_sequence A079155 A079156 A079157

base,more,nonn

Jason Earls (zevi_35711(AT)yahoo.com) and Robert G. Wilson v (rgwv(AT)rgwv.com), Dec 27 2002