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A145991 Final prime in a run of more than 1 consecutive primes == 1 (mod 4).

%I A145991 #8 Jul 03 2016 00:17:34
%S A145991 17,41,101,113,197,233,281,317,353,409,461,521,617,677,709,773,809,
%T A145991 857,881,941,1013,1097,1117,1217,1249,1301,1381,1433,1493,1553,1601,
%U A145991 1613,1657,1697,1721,1741,1801,1877,1901,1949,1997,2081,2129,2141,2161,2237
%N A145991 Final prime in a run of more than 1 consecutive primes == 1 (mod 4).
%D A145991 Enoch Haga, Exploring Primes on Your PC and the Internet, 1994-2007. Pp. 30-31. ISBN 978-1-885794-24-6
%e A145991 a(1)=17 because this sequence includes consecutive runs of any length and this ending term > 1 in a run of 2 (comprising 13 and 17) is 17.
%o A145991 (UBASIC)
%o A145991 10 'cluster primes
%o A145991 20 C=1
%o A145991 30 input "end #";L
%o A145991 40 for N=3 to L step 2
%o A145991 50 S=int(sqrt(N))
%o A145991 60 for A=3 to S step 2
%o A145991 70 B=N/A
%o A145991 80 if int(B)*A=N then cancel for:goto 170
%o A145991 90 next A
%o A145991 100 C=C+1
%o A145991 110 E=N/4:E=int(E):R=N-(4*E)
%o A145991 120 if R=1 then print N;:C1=C1+1:T1=T1+1:print T1
%o A145991 130 if R=3 then T1=0
%o A145991 140 if R=3 then print " ";N;:C3=C3+1:T2=T2+1:print T2
%o A145991 150 if R=1 then T2=0
%o A145991 160 if T1>10 or T2>10 then stop
%o A145991 170 next
%o A145991 180 print "Total primes=";C;:print "Type A";C1;"Type B";C3
%Y A145991 Cf. A055623, A054624, A145986, A145988- A145994
%K A145991 easy,nonn
%O A145991 1,1
%A A145991 _Enoch Haga_, Oct 26 2008