19835

Appears in sequences

• Numbers n such that 103*2^n-1 is prime.at n=21A050577
• Triangle read by rows: T(n,k) is number of peakless Motzkin paths of length n and having k uhh...hd's starting at level 0, where u=(1,1), h=(1,0) and d=(1,-1) (can be easily expressed using RNA secondary structure terminology).at n=52A098071
• Numbers n such that 8*10^n + 5*R_n + 2 is prime, where R_n = 11...1 is the repunit (A002275) of length n.at n=3A103085
• Number of 3Xn arrays containing n copies of 0..3-1 with no element 1 greater than its west, northeast or northwest neighbor modulo 3 and the upper left element equal to 0.at n=14A266995
• a(n) = Sum_{k=1..n} k * tau(k)^2, where tau is A000005.at n=40A320896
• Numbers of the form ab such that phi(ab) = a*b - 1 where ab is the concatenation of a and b.at n=3A336192
• Number of ways to write n as an ordered sum of 5 prime powers (including 1).at n=39A341134