A087430 Nonprimes n with gpf(n) > gpf(n+1), where gpf=A006530 (greatest prime factor).

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

Robert Israel, Table of n, a(n) for n = 1..10000

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

Adjacent sequences: A087427 A087428 A087429 * A087431 A087432 A087433

Keyword

nonn

Author

Reinhard Zumkeller, Sep 02 2003

Status

approved