Initial data commit

Task/Mertens-function/Fortran/mertens-function.f

@@ -0,0 +1,40 @@
+      program Mertens
+      implicit none
+      integer M(1000), n, k, zero, cross
+
+C     Generate Mertens numbers
+      M(1) = 1
+      do 10 n=2, 1000
+          M(n) = 1
+          do 10 k=2, n
+              M(n) = M(n) - M(n/k)
+ 10   continue
+
+C     Print table
+      write (*,"('The first 99 Mertens numbers are:')")
+      write (*,"('   ')",advance='no')
+      k = 9
+      do 20 n=1, 99
+          write (*,'(I3)',advance='no') M(n)
+          k = k-1
+          if (k .EQ. 0) then
+              k=10
+              write (*,*)
+          end if
+ 20   continue
+
+C     Calculate zeroes and crossings
+      zero = 0
+      cross = 0
+      do 30 n=2, 1000
+          if (M(n) .EQ. 0) then
+              zero = zero + 1
+              if (M(n-1) .NE. 0) cross = cross+1
+          end if
+ 30   continue
+
+ 40   format("M(N) is zero ",I2," times.")
+      write (*,40) zero
+ 50   format("M(N) crosses zero ",I2," times.")
+      write (*,50) cross
+      end program