27663 is the END of a run of five consecutive semiprimes with only one non-semiprime intervening. Here the semiprimes are:

27663 = 3 * 9221

27662 = 2 * 13831

27661 = 139 * 199

27660 = 2^2 * 3 * 5 * 461

27659 = 17 * 1627

27658 = 2 * 13829

The sequence can be generated as follows:

INPUT

span=4

S=[]

for n in [1..40000]:

  F=list(factor(n))

  sum=0

  for f in F:

    sum+=f[1]

  if sum==2 and is_square(n)==0:

    S.append(n)

# print(S)     

L=[]

for i in range(len(S)-span):

  if S[i+span]-S[i]==span+1:

    L.append(S[i+span])

print(L)

print(len(L))

OUTPUT

[146, 206, 218, 219, 303, 699, 1142, 1766, 3903, 4538, 6002, 7118, 7863, 9939, 11762, 14258, 16442, 20019, 20283, 22238, 27386, 27519, 27663, 32138, 34418, 35198, 36123, 38163, 38942, 39687]

30

27663 is an interprime, cyclic, lucky, energetic and D-number.

27663 can be rendered as a digit equation as follows:

2 + 7 = 6 + 6 - 3