OFFSET
1,1
COMMENTS
The sequence has prime factorization (13*197)^12, (13*1093)^12, (13*1733)^12, (13*17*139)^12, (13*7877)^12, (13*16069)^12.
FORMULA
a(n) = is the n-th number rf such that both rf and rf-1 are refactorable and 13 is the smallest prime divisor of rf.
EXAMPLE
a(1)=(13*197)^12 is the first number rf such that rf refactorable, 13 is the smallest prime of rf and rf-1 is refactorable.
CROSSREFS
KEYWORD
nonn,bref
AUTHOR
Walter Kehowski, Jun 22 2006
STATUS
approved