A174385 Product of 3 consecutive odd numbers n such that n+-2 are primes.

15, 105, 315, 79335, 148665, 300495, 1860375, 1952625, 3048045, 6538455, 14347935, 57065085, 82311135, 83451705, 169110165, 223646115, 335699595, 347426115, 410169435, 674522625, 736310715, 1015071105, 1655590755

Offset

1,1

Comments

All terms are divisible by 15. - Robert Israel, Apr 10 2018

Links

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

Example

1*3*5=15 and 15+2 and 15-2 are primes, so 15=a(1) is in the sequence.
3*5*7=105 and 105+2 and 105-2 are primes, so 105=a(2) is in the sequence.

Maple

select(t -> isprime(t+2) and isprime(t-2), [seq(n*(n+2)*(n+4), n=1..2000, 2)]); # Robert Israel, Apr 10 2018

Mathematica

f[n_]:=n*(n+2)*(n+4); Select[Table[f[n], {n, 1, 7!, 2}], PrimeQ[ #-2]&&PrimeQ[ #+2]&]
Select[Times@@@Partition[Range[1, 1201, 2], 3, 1], AllTrue[#+{2, -2}, PrimeQ]&] (* The program uses the AllTrue function from Mathematica version 10 *) (* Harvey P. Dale, May 17 2018 *)

Crossrefs

Cf. A174383, A174384

Sequence in context: A335672 A160892 A061550 * A185129 A090454 A240440

Adjacent sequences: A174382 A174383 A174384 * A174386 A174387 A174388

Keyword

nonn

Author

Vladimir Joseph Stephan Orlovsky, Mar 17 2010

Extensions

Edited by Robert Israel, Apr 10 2018

Status

approved