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A265693
Squarefree composites that are not sqrt(n)-smooth: some prime factor of n is > sqrt(n).
1
6, 10, 14, 15, 21, 22, 26, 33, 34, 35, 38, 39, 42, 46, 51, 55, 57, 58, 62, 65, 66, 69, 74, 77, 78, 82, 85, 86, 87, 91, 93, 94, 95, 102, 106, 110, 111, 114, 115, 118, 119, 122, 123, 129, 130, 133, 134, 138, 141, 142, 143, 145, 146, 155, 158, 159, 161, 166, 170, 174
OFFSET
1,1
COMMENTS
Intersection of A064052 and A120944. - Michel Marcus, Dec 15 2015
LINKS
EXAMPLE
a(13) = 42 = 2*3*7. It is squarefree, composite and 7 > sqrt(42) = 6.4807...
MAPLE
filter:= proc(n)
if isprime(n) or not numtheory:-issqrfree(n) then return false fi;
max(numtheory:-factorset(n))^2 > n
end proc:
select(filter, [$2..1000]); # Robert Israel, Nov 04 2019
MATHEMATICA
JaggedQ[n_] := If[Last[FactorInteger[n]][[1]]>Sqrt[n], True, False]; Select[Range[200], JaggedQ[#]&&SquareFreeQ[#]&&!PrimeQ[#] &]
PROG
(PARI) lista(nn) = {forcomposite(n=1, nn, if (issquarefree(n), my(f = factor(n)); if (f[#f~, 1]^2 > n, print1(n, ", "))); ); } \\ Michel Marcus, Dec 15 2015
CROSSREFS
Includes A006881.
Sequence in context: A238748 A367590 A268390 * A211484 A339561 A350486
KEYWORD
nonn
AUTHOR
Frank M Jackson, Dec 13 2015
STATUS
approved