146090domain: NAppears in sequencesa(n) = floor(concatenation of n+5, n+4, n+3, n+2, n+1 and n divided by 6).at n=3A075007a(1)=1, a(n+1) = a(n) + spf(Sum_{i=1..n} a(i)), where spf=A020639 (smallest prime factor).at n=40A080180Number of symmetric primitive Lucas strings of length n.at n=34A250112