OFFSET
1,3
FORMULA
For n>7 a(3n)=a(n)+2; a(3n+1)=a(n)+3; (3n+2)=a(n)+4
PROG
(PARI) a(n)=if(n<2, 1, n-2*valuation(n!*sum(i=1, n, 1/i), 3))
CROSSREFS
KEYWORD
nonn
AUTHOR
Benoit Cloitre, Mar 09 2004
STATUS
approved