OFFSET
1,2
COMMENTS
The final terms of the arithmetic progressions defined in A083785. - N. J. A. Sloane, Oct 18 2007
a(8) > 10^13. - Donovan Johnson, Oct 20 2009. [See Reble link for an upper limit.]
The main entry is A034173, which should be updated whenever something relevant is added here. - M. F. Hasler, Oct 28 2012
LINKS
Don Reble, a(8) < 1.9*10^42, SeqFan list, Oct 23 2012
FORMULA
a(n) = A034173(n) + n - 1. - Max Alekseyev, Nov 10 2009
EXAMPLE
a(4)=19943 because 19940, ..., 19943 all have the form p^2 q r.
PROG
(PARI) A034174(n)={my(f); for(k=n, 9e9, f=0; for(i=0, n-1, f==(f=vecsort(factor(k-i)[, 2])) || !i || [k+=n-i-1; next(2)]); return(k))} \\ For illustrative purpose; not useful for n>=6. - M. F. Hasler, Oct 28 2012
CROSSREFS
KEYWORD
hard,nonn,more
AUTHOR
Dean Hickerson, Oct 01 1998
EXTENSIONS
a(7) from Donovan Johnson, Oct 20 2009
STATUS
approved