17993

Appears in sequences

• Numbers k such that 219*2^k+1 is prime.at n=36A032486
• Composite numbers whose divisors (except 1) all contain the digit 9.at n=32A062680
• Triangle read by rows: T(n,k) is the number of Motzkin paths of length n having k low humps. (A hump is an upstep followed by 0 or more flatsteps followed by a downstep. A low hump is a hump that starts at level zero.).at n=58A097887
• Numbers with ordered partitions that have periods of length 5.at n=37A178572
• Least semiprime m such that the previous semiprime is m - A215231(n).at n=11A217851
• Number of minimal edge covers in the n-wheel graph.at n=15A290471
• a(1) = 0, a(2) = 1, and for n > 2, a(n) = 2*a(A252463(n)) + [n == 1 (mod 2)]*[J(3|n) == 1], where J is the Jacobi-symbol.at n=46A292253
• Number of compositions (ordered partitions) of n into distinct parts >= 7.at n=60A339108