FUNCTION:  partitions[ptnRR] - Rogers-Ramanujan partitions
 
CALLING SEQUENCE:  ptnRR(ptn)
 
PARAMETERS:    ptn - partition
                           
GLOBAL VARIABLES: NONE  

SYNOPSIS:  
   Returns true if ptn is a partition in which difference between parts
   is at least 2.
                    
EXAMPLES:  
                    
> with(combinat):
> with(partitions):
> ptns:=partition(8):
> ptns1:=select(ptnRR,ptns);
                     ptns1 := [[3, 5], [2, 6], [1, 7], [8]]

> ptns2:=select(ptn-> if convert(modp(ptn,5),set) subset {1,4} then true 
  else false fi, ptns);
    ptns2 := [[1, 1, 1, 1, 1, 1, 1, 1], [1, 1, 1, 1, 4], [4, 4], [1, 1, 6]]

> nops(ptns), nops(ptns1), nops(ptns2);
                                    22, 4, 4

DISCUSSION:  There are 22 partitions of 8.
             Of these 4 satisfy the condition (listed)
             We also find the partitions of 8 with parts congruent to
             1 or 4 mod 5.
                    
SEE ALSO: PRR