OFFSET
1,1
COMMENTS
Membership in this sequence depends only on the prime signature, see PARI script. - Charles R Greathouse IV, Oct 19 2015
LINKS
Charles R Greathouse IV, Table of n, a(n) for n = 1..10000
EXAMPLE
12 is not a member as tau(12) = 6 and there are four terms 2,3,4 and 6 that divide 12.
PROG
(PARI) has(f)=f=select(n->n, f); if(#f==0, return(0)); if(#f==1 && f[1]<4, return(1)); my(t=prod(i=1, #f, f[i]+1)\2); forvec(x=vector(#f, i, [0, f[i]]), if(x==f, return(1)); t-=has(x); if(t<0, return(0)))
is(n)=has(factor(n)[, 2]~) \\ Charles R Greathouse IV, Oct 19 2015
CROSSREFS
KEYWORD
nonn
AUTHOR
Amarnath Murthy, May 29 2003
EXTENSIONS
More terms from David Wasserman, Dec 20 2004
STATUS
approved