OFFSET
1,1
COMMENTS
Semiprime analogous to A056815.
EXAMPLE
14 is in the sequence because 14 is a semiprime (2*7) and its "Look and Say", 1114 is also a semiprime (2*557).
MATHEMATICA
LookAndSayA[n_] := FromDigits@ Flatten@ IntegerDigits@ Flatten[ Through[ {Length, First}[#]] & /@ Split@ IntegerDigits@ n]; semiPrimeQ[n_] := Plus @@ Last /@ FactorInteger@ n == 2; Select[ Range@ 650, semiPrimeQ@# && semiPrimeQ@ LookAndSayA@# &]
CROSSREFS
KEYWORD
easy,nonn
AUTHOR
Robert G. Wilson v, Jan 27 2012
STATUS
approved