22579200

Appears in sequences

• Numbers k with the property that in the prime factorization of k all prime exponents are prime, their sum is also prime and equals the sum of distinct prime factors of k.at n=9A071837
• A triangular sequence from umbral calculus expansion of _Simon Plouffe_'s rational polynomial for A002890: p(x,t) = exp(x*t)*(1 - 6*t + 9*t^2 - 4*t^3 + t^4)/(4*t - 1)/(2*t - 1).at n=36A137514
• a(n) = denominator((1/n!)*Sum_{k=1..n} 1/(2*k)).at n=8A377401