42001

Appears in sequences

• Strong pseudoprimes to base 54.at n=20A020280
• Numbers whose set of base-14 digits is {1,4}.at n=36A032826
• Expansion of x^2/((1-x)*(1+2*x)*(1-6*x)).at n=8A091056
• Least positive integer k such that both k and k*n belong to the set {m>0: 2*prime(prime(m))+1 = prime(p) for some prime p}.at n=24A261362
• Expansion of e.g.f. exp(x) / (1 - x^4).at n=8A330045
• a(n) = (4*n)! * Sum_{k=0..n} 1 / (4*k)!.at n=2A337727
• a(n) = n! * Sum_{k=0..floor(n/4)} 1 / (4*k)!.at n=8A352660
• 11-gonal numbers which are products of two distinct primes.at n=14A354448
• Expansion of e.g.f. exp( x * exp(x^3) ).at n=8A354553
• E.g.f. satisfies A(x) = exp(x*A(x^3)).at n=8A367719