OFFSET
1,2
COMMENTS
a(971)=325850. No more terms?
Almost surely the above conjecture is true, but it is currently hopeless to prove. It would follow from prime gaps being less than about the cube root, but this is not known even under RH. - Charles R Greathouse IV, Jun 10 2017
MATHEMATICA
Select[Range@ 128, EvenQ@ Mod[Times @@ Take[#, 3], #[[4]]] &@ Prime[# + Range[0, 3]] &] (* Michael De Vlieger, Jun 09 2017 *)
Position[Partition[Prime[Range[140]], 4, 1], _?(EvenQ[Mod[Times@@Take[#, 3], #[[4]]]]&)]//Flatten//Quiet (* Harvey P. Dale, Oct 14 2020 *)
PROG
(PARI) isok(n) = (((prime(n)*prime(n+1)*prime(n+2)) % prime(n+3)) % 2) == 0; \\ Michel Marcus, Jun 07 2017
(PARI) list(lim)=my(v=List(), p=2, q=3, r=5, n); forprime(s=7, , if(n++>lim, break); if(p*q*r%s%2==0, listput(v, n)); p=q; q=r; r=s); Vec(v) \\ Charles R Greathouse IV, Jun 10 2017
CROSSREFS
KEYWORD
nonn
AUTHOR
Zak Seidov, Jun 06 2017
STATUS
approved