All numbers of the forms 3a*5b*7c, 3a-1*5b*6*7c or 3a-2*5b*62*7c must be checked. d(n,m) must not contain a zero or or more than 2 even digits. Maximal a+b+c without holding the above criteria was 139. All numbers with a+b+c<=1000 were checked. Only the last 35 digits were needed.
