Numbers n such that d(n-1) = d(n+1) = 6, where d(k) is the number of divisors of k (A000005).

Terms

a(0) =19a(1) =51a(2) =243a(3) =244a(4) =424a(5) =476a(6) =604a(7) =638a(8) =723a(9) =846a(10) =926a(11) =1683a(12) =1774a(13) =2008a(14) =2524a(15) =2526a(16) =2528a(17) =3124a(18) =3176a(19) =3178a(20) =4204a(21) =4476a(22) =4526a(23) =4924a(24) =5824a(25) =6726a(26) =6812a(27) =6963a(28) =7300a(29) =7443