43697

Appears in sequences

• Semiprimeth recurrence: a(0) = 1, a(n+1) = semiprime(a(n)) = A001358(a(n)).at n=9A105999
• a(n) = a(n-1) + Sum_{k=0..floor(log_2(n-1))} a(2^k), a(1) = 1.at n=34A133147
• Numbers k for which (k!-3)/3 is prime.at n=13A139056
• Number of vertices in an equal-armed cross with arms of length n (see Comments in A331456 for definition).at n=8A333035