OFFSET
1,1
COMMENTS
More precisely, scan A004154, subtract 1 and record the answer if it is a prime. The sequence is not monotonic.
LINKS
Charles R Greathouse IV, Table of n, a(n) for n = 1..17
MAPLE
A004154 := proc(n) option remember ; local m ; if n <= 1 then RETURN(1) ; else m := A004154(n-1)*n ; while m mod 10 = 0 do m := m /10 ; end ; RETURN(m) ; fi ; end: n := 1 ; while true do f := A004154(n) : if isprime(f-1) then printf("%d, ", f-1) ; fi ; n := n+1 : od : # R. J. Mathar, Feb 27 2007
PROG
(PARI) v=[]; for(n=1, 500, if(ispseudoprime(t=n!/10^valuation(n!, 5)-1), v=concat(v, t))); v \\ Charles R Greathouse IV, Feb 14 2011
CROSSREFS
KEYWORD
nonn
AUTHOR
Cino Hilliard, Dec 23 2002
EXTENSIONS
More terms from R. J. Mathar, Feb 27 2007
STATUS
approved