1,1

Enoch Haga, Exploring Primes on Your PC and the Internet, 1994-2007. Pp. 30-31. ISBN 978-1-885794-24-6

a(1)=11 because this sequence includes consecutive runs of any length >1 and this ending term in a run of 2 is 11.

(Other) UBASIC: 10 'cluster primes 20 C=1 30 input "end #"; L 40 for N=3 to L step 2 50 S=int(sqrt(N)) 60 for A=3 to S step 2 70 B=N/A 80 if int(B)*A=N then cancel for:goto 170 90 next A 100 C=C+1 110 E=N/4:E=int(E):R=N-(4*E) 120 if R=1 then print N; :C1=C1+1:T1=T1+1:print T1 130 if R=3 then T1=0 140 if R=3 then print " "; N; :C3=C3+1:T2=T2+1:print T2 150 if R=1 then T2=0 160 if T1>10 or T2>10 then stop 170 next 180 print "Total primes="; C; :print "Type A"; C1; "Type B"; C3

A055623 A054624 A145986 A145988 A145989 A145990 A145991 A145992 A145993

Sequence in context: A068231 A073024 A161897 this_sequence A139834 A100558 A126199

Adjacent sequences: A145991 A145992 A145993 this_sequence A145995 A145996 A145997

easy,nonn

Enoch Haga (Enokh(AT)comcast.net), Oct 26 2008