18533
domain: N
Appears in sequences
- a(n)=a(n-1)+a(n-4).at n=30A014098
- Powers of fifth root of 18 rounded up.at n=17A018167
- a(n) = 10*n^2+n.at n=42A055437
- Numbers k such that 3*R_k - 2 is prime, where R_k = 11...1 is the repunit (A002275) of length k.at n=23A055557
- Semiprimes of form p*q with p < q, such that 2^p - 1 == 0 (mod q).at n=10A179768
- The sum a(n) + a(n+1) is visible around the comma that follows a(n+1). See the Comments and Example sections for details.at n=10A334829
- a(1) = 1; a(n) = a(n-1) + 2 * a(floor(n/2)).at n=38A347027