2 c diverses operations sur les entiers 4, 5, 6
3 c=======================================================================
4 c per4a6 : entier pour la permutation circulaire (4,5,6)
5 c per4a6(-1,i) = entier avant i
7 c per4a6( 1,i) = entier apres i
8 c per4a6( 2,i) = entier 2 places apres i = per4a6(-1,i)
9 c per4a6(-1,4) = 6, per4a6(-1,5) = 4, per4a6(-1,6) = 5
10 c per4a6( 0,4) = 4, per4a6( 0,5) = 5, per4a6( 0,6) = 6
11 c per4a6( 1,4) = 5, per4a6( 1,5) = 6, per4a6( 1,6) = 4
12 c per4a6( 2,4) = 6, per4a6( 2,5) = 4, per4a6( 2,6) = 5
13 c-----------------------------------------------------------------------
14 integer per4a6(-1:2,4:6)
15 common /ope4a6/ per4a6