OFFSET
1,1
LINKS
Charles R Greathouse IV, Table of n, a(n) for n = 1..10000
EXAMPLE
10 is in this sequence because A001221(10) = 2 and 10 is not divisible by a square greater than 4.
MATHEMATICA
With[{nn = 10^4, r = 2}, Take[#, 67] &@ Union@ Flatten@ Table[Function[p, {p*2^Range[Log2[nn/p]], p DeleteCases[Prime@ Range[r, PrimePi[nn/p]], q_ /; q == p]}]@ Prime@ n, {n, r, PrimePi[nn/Prime[r]]}]] (* Michael De Vlieger, Jul 10 2017 *)
PROG
(PARI) list(lim)=my(v=List()); forprime(p=5, lim\3, forprime(q=3, min(lim\p, p-2), listput(v, p*q))); for(e=1, logint(lim\3, 2), forprime(p=3, lim>>e, listput(v, p<<e))); Set(v) \\ Charles R Greathouse IV, Aug 09 2017
CROSSREFS
KEYWORD
nonn,easy
AUTHOR
Juri-Stepan Gerasimov, Jul 08 2017
STATUS
approved