OFFSET
1,1
LINKS
Robert Israel, Table of n, a(n) for n = 1..10000
EXAMPLE
In the set of products of primes and factorials 10 (= 5 times factorial 2) is the seventh largest number and therefore is the seventh member of the sequence.
MAPLE
N:= 1000: # to get all terms <= N
P:= select(isprime, [2, seq(i, i=3..N, 2)]):
F:= 1: v:= 1:
for n from 2 do
v:= v*n;
if v > N then break fi;
F:= F, v;
od:
F:= {F}:
sort(convert(select(`<=`, {seq(seq(p*f, f=F), p=P)}, N), list)); # Robert Israel, Aug 27 2018
MATHEMATICA
With[{upto=140}, Select[Union[Flatten[Table[p*f, {p, Prime[ Range[ PrimePi[ upto]]]}, {f, Range[10]!}]]], #<=upto&]] (* Harvey P. Dale, Jul 19 2019 *)
CROSSREFS
KEYWORD
nonn
AUTHOR
Axel Harvey, Oct 15 2004
STATUS
approved