OFFSET
1,1
COMMENTS
Semiprime analog of A076656 a(1) = 2; a(n) is smallest prime > 3*a(n-1). a(n)-a(n-1) is often 1, never more than 16 through n = 28, then jumps to 32 for n = 29; and I wonder what its value or mean value is asymptotically as a function of n.
MATHEMATICA
nxt[n_]:=Module[{c=3n, k=1}, While[PrimeOmega[c+k]!=2, k++]; c+k]; NestList[ nxt, 1, 30] (* Harvey P. Dale, May 31 2012 *)
CROSSREFS
KEYWORD
easy,nonn,less
AUTHOR
Jonathan Vos Post, May 04 2006
STATUS
approved