OFFSET
1,1
COMMENTS
Suggested by Carlos Rivera's Puzzle 429 which asks for runs where p+2 is biprime.
EXAMPLE
a(2)=29 because this is the first prime in a run of 2 where p+4 is semiprime (3*11).
PROG
(UBASIC) 10 'p+4 is biprime 20 N=1 30 A=3:S=sqrt(N) 40 B=N\A: if B*A=N then N=N+2:goto 30 50 A=A+2: if A<=S then 40 60 C=C+1:O=N+4:D=prmdiv(O):E=O\D 70 if E<>prmdiv(E) or E=1 then C=0:goto 90 80 print C; N; D; E; O: if C>=10 then stop 90 N=N+2:goto 30
CROSSREFS
KEYWORD
more,nonn
AUTHOR
Enoch Haga, Jan 30 2008
EXTENSIONS
a(1) corrected and a(11)-a(15) from Giovanni Resta, Jun 22 2018
STATUS
approved