OFFSET
1,1
LINKS
Charles R Greathouse IV, Table of n, a(n) for n = 1..10000
MATHEMATICA
Length /@ DeleteCases[Split@ Table[Boole@ And[# != 1, PrimeOmega@ # <= 2] &[# + 2] &@ Prime@ n, {n, 300}], k_ /; Total@ k == 0] (* Michael De Vlieger, Feb 27 2017 *)
PROG
(PARI) do(lim)=my(v=List(), u=v, r, s=1); forprime(p=2, lim\2, forprime(q=2, min(lim\p, p), listput(u, p*q))); u=Set(u); r=3; forprime(p=5, lim, if(p-r==2 || setsearch(u, r+2), s++, if(s, listput(v, s); s=0)); r=p); u=0; Vec(v) \\ Charles R Greathouse IV, Feb 27 2017
CROSSREFS
KEYWORD
nonn
AUTHOR
Enrique Navarrete, Feb 21 2017
STATUS
approved