OFFSET
2,3
LINKS
Harry J. Smith and Max Alekseyev, Table of n, a(n) for n = 2..135
FORMULA
For n>2, a(n) = (d + (m)/d)/2 - floor(sqrt(m)), where m=n!-1 and d is the smallest divisor of m such that d >=sqrt(m). - Max Alekseyev, Apr 13 2009
PROG
(PARI) { a(n) = my(m); if(n==2, return(1)); m=n!-1; fordiv(m, d, if(d*d>=m, return((d+m\d)\2-sqrtint(m)); ); ) } /* Max Alekseyev, Apr 13 2009 */
CROSSREFS
KEYWORD
hard,nonn
AUTHOR
Jason Earls, May 09 2004
EXTENSIONS
Extended by Max Alekseyev, Apr 13 2009
a(60)-a(135) from Max Alekseyev, Dec 29 2015
STATUS
approved