OFFSET
1,2
EXAMPLE
a(5) = 6 because the next prime or semiprime after 241 is 247, and that is a record gap of size 6.
PROG
(PARI) checkrange(a, b, r)=while(b-a>r, forstep(n=a+r, a+1, -1, if(bigomega(n)<3, a=n; next(2))); for(n=a+r+1, b, if(bigomega(n)<3, return([a, n])))); 0
print1(1); p=5; r=1; forprime(q=7, 1e9, if(q-p<=r, p=q; next); t=checkrange(p, q, r); while(t, print1(", "t[2]-t[1]); t=checkrange(t[2], q, r=t[2]-t[1])); p=q) \\ Charles R Greathouse IV, Nov 19 2016
CROSSREFS
KEYWORD
nonn,more
AUTHOR
Bobby Jacobs, Nov 13 2016
EXTENSIONS
a(32)-a(37) from Giovanni Resta, Apr 25 2020
STATUS
approved