OFFSET
1,1
EXAMPLE
71, 499 and 1223, for instance, belong to the sequence because their respective descriptions 1171 (1 once, 7 once), 9241 (9 twice, 4 once), 312211 (3 once, 2 twice, 1 once) are all primes.
MATHEMATICA
LookAndSayB[ n_] := FromDigits@Flatten@((Through[ {First, Length}[ # ] ] &) /@ Split@Reverse@IntegerDigits@n); Select[Prime@Range[400], PrimeQ@LookAndSayB@# &] (* Ray Chandler, Jan 16 2007 *)
CROSSREFS
KEYWORD
nonn,base
AUTHOR
Lekraj Beedassy, Jan 07 2007
EXTENSIONS
Corrected by Ray Chandler, Jan 16 2007
STATUS
approved