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A143957 An integer >= 2 is included if {the difference between the largest and smallest primes dividing n} divides n+1. 2
6, 12, 14, 15, 18, 20, 24, 35, 36, 39, 44, 45, 48, 50, 54, 63, 72, 75, 80, 84, 96, 108, 119, 135, 143, 144, 147, 152, 153, 155, 162, 175, 192, 200, 208, 216, 224, 225, 230, 231, 242, 245, 275, 279, 288, 294, 299, 315, 320, 323, 324, 374, 375, 384, 399, 405, 429 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,1

LINKS

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

EXAMPLE

The largest prime dividing 14 is 7. The smallest prime dividing 14 is 2. 7-2=5 divides 14+1=15. So 14 is in the sequence.

MAPLE

filter:= proc(n) local P;

  P:= numtheory:-factorset(n);

  if nops(P) = 1 then return false fi;

  n+1 mod (max(P)-min(P)) = 0

end proc:

select(filter, [$2..1000]); # Robert Israel, Nov 04 2020

MATHEMATICA

Select[Range[2, 429], If[Or[PrimeQ[#], PrimePowerQ[#]], False, Mod[#1, Last[#2] - First[#2]] == 0 & @@ {# + 1, FactorInteger[#][[All, 1]]}] &] (* Michael De Vlieger, Nov 04 2020 *)

CROSSREFS

Cf. A143958.  Includes A037074.

Sequence in context: A055051 A338054 A336559 * A318981 A105115 A325700

Adjacent sequences:  A143954 A143955 A143956 * A143958 A143959 A143960

KEYWORD

nonn

AUTHOR

Leroy Quet, Sep 05 2008

EXTENSIONS

Extended by Ray Chandler, Nov 07 2008

STATUS

approved

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Last modified May 14 05:29 EDT 2021. Contains 343872 sequences. (Running on oeis4.)