C First occurrence of a string of exactly n consecutive twin prime pairs
C Hugo Pfoertner, http://www.pfoertner.org/
C
C Oct 15 2003 Initial version
      logical isprim, prime
C
C Set m = 4 + 2*(target number of twin pairs)
C...+....1....+....2....+....3....+....4....+....5....+....6....+....7..
C Examples: m=10 for OEIS A035791, m=8 for A035790, m=6 for A035789
C 
      parameter (m=10)
      integer p(m)
C Primality checker from
C http://www.enginemonitoring.net/math/isprim.txt
      external isprim
c
      p(1) = 3
      p(2) = 5
      p(3) = 7
      p(4) = 11
      p(5) = 13
      p(6) = 17
c
      j = 6
      do 10 i = 19, 101, 2
      if ( isprim(i) ) then
        j = j + 1
        if ( j .gt. m ) goto 20
        p(j) = i
      endif
10    continue
20    continue
c
      found = 0
      do 100 i = p(m)+2, 2147483647, 2
      if ( isprim(i) ) then
        do 110 j = 1, m
        p(j) = p(j+1)
110     continue
        p(m) = i
c Preceding adjacent two primes must not be twin primes
        if ( p(2)-p(1) .eq. 2 ) goto 100
c Check for consecutive twin pairs
        do 120 k = 3, m-3, 2
        if ( p(k+1)-p(k) .ne. 2 ) goto 100
120     continue
c Following adjacent two primes must not be twin primes
        if ( p(m)-p(m-1) .eq. 2 ) goto 100
c
        found = found + 1
        write (*,1000) (p(l),l=3,m-2)
C Adjust format for m>12
1000  format ( 8i10 )
C Stop after 100 occurrences
        if ( found .gt. 100 ) stop
c
      endif
100   continue
      end