A140776 A number n is included if (p + n/p) is prime, where p is the largest prime that divides n.

2, 6, 10, 12, 22, 24, 28, 30, 34, 40, 42, 48, 52, 58, 60, 66, 70, 76, 78, 82, 84, 88, 90, 102, 112, 118, 120, 130, 132, 138, 142, 148, 160, 168, 172, 180, 184, 186, 190, 192, 198, 202, 204, 208, 210, 214, 220, 222, 228, 232, 234, 238, 240, 246, 252, 268, 270, 274

Offset

1,1

Comments

All terms are even. - Robert Israel, Feb 04 2018

Links

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

Example

The largest prime dividing 48 is 3. Since 3 + 48/3 = 19 is prime, then 48 is included in this sequence.

Maple

filter:= proc(n) local p;
  p:= max(numtheory:-factorset(n));
  isprime(p+n/p)
end proc:
select(filter, 2*[$1..1000]); # Robert Israel, Feb 04 2018

Mathematica

fQ[n_] := Block[{p = Last@ First@ Transpose@ FactorInteger@n}, PrimeQ[p + n/p] == True]; Select[ Range[2, 279], fQ@# &] (* Robert G. Wilson v, May 30 2008 *)

Crossrefs

Cf. A140775, A140777.

Sequence in context: A071638 A028348 A214963 * A277238 A108783 A235989

Adjacent sequences: A140773 A140774 A140775 * A140777 A140778 A140779

Keyword

nonn

Author

Leroy Quet, May 29 2008

Extensions

More terms from Robert G. Wilson v, May 30 2008

Status

approved