83220

Appears in sequences

• Base-4 digits are, in order, the first n terms of the periodic sequence with initial period 1,1,0.at n=8A033131
• Numbers k such that (k-1, k+1) and (k/2-1, k/2+1) are both pairs of twin primes.at n=12A076504
• a(n) is a non-palindromic composite located between twin primes whose reverse, which is less than it, is also located between twin primes.at n=33A103741
• Number of subsets of {1,2,...,n} whose sum is semiprime (cf. A001358, A064911).at n=17A181522
• Triangular array read by rows: T(n,k) (2 <= k <= n) is the smallest number whose representations in bases n and k both consist of repeated identical blocks of digits.at n=34A317168
• Complement of A340745.at n=11A340824