OFFSET
1,6
PROG
(PARI) a(n)=my(m=-1, P=prod(i=2, n, 2*i-1)); while(m+=2, for(k=m-2, m-1, forstep(M=1, m-2, 2, if(ispseudoprime(P/M+2^k), return(k)))); for(k=0, m, if(ispseudoprime(P/m+2^k), return(m)))) \\ Charles R Greathouse IV, Feb 27 2013
CROSSREFS
KEYWORD
nonn
AUTHOR
Vladimir Shevelev, Feb 15 2013
EXTENSIONS
Terms beginning with a(6) were calculated by Peter J. C. Moses.
STATUS
approved