collatz(n)=
{
m=n; l=listcreate(60000); listput(l,m); i=1; distinct=1;\
while(distinct, if(m%2==0,m=m/2,m=3*m+1); i=i+1; j=1; listput(l,m);\
while(j<i && distinct==1, if(m==l[j],distinct=0,j=j+1)));\
print();\
print("Starting value    = ",n);\
print("Length            = ",i-1);\
print("Terminating value = ",l[i-1]);\
print();\
print("To see the whole sequence type l");\
print();\
}

addhelp(collatz , "collatz(n) : calculates the length and terminating value of the 3n+1 algorithm (assuming it terminates after less than 60000 steps).")

printp("collatz(n) : calculates the length and terminating value of the 3n+1 algorithm with starting value n.")