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A087430
Nonprimes n with gpf(n) > gpf(n+1), where gpf=A006530 (greatest prime factor).
2
14, 15, 26, 34, 35, 38, 39, 44, 49, 51, 55, 62, 63, 65, 69, 74, 76, 80, 86, 87, 94, 95, 99, 104, 111, 116, 118, 119, 122, 123, 124, 129, 134, 142, 143, 146, 152, 153, 155, 158, 159, 161, 164, 174, 183, 185, 186, 188, 194, 195, 202, 203, 206, 207, 209, 214, 215
OFFSET
1,1
COMMENTS
Subsequence of A070087.
LINKS
MAPLE
N:= 1000: # to get all terms < N
V:= Vector(N):
p:= 1:
do
p:= nextprime(p);
if p > N then break fi;
V[[seq(k*p, k=1..N/p)]]:= p
od:
select(t -> V[t] > V[t+1] and not isprime(t), [$1..N-1]); # Robert Israel, Jul 03 2018
MATHEMATICA
With[{nn=250}, Select[Complement[Range[nn], Prime[Range[PrimePi[ nn]]]], FactorInteger[ #][[-1, 1]]>FactorInteger[#+1][[-1, 1]]&]] (* Harvey P. Dale, Jul 14 2016 *)
CROSSREFS
Cf. A087429.
Sequence in context: A090066 A084429 A207036 * A085900 A075659 A022104
KEYWORD
nonn
AUTHOR
Reinhard Zumkeller, Sep 02 2003
STATUS
approved