280665

Appears in sequences

• a(n) = ((6*n+9)(!^6))/9(!^6), related to A034723 (((6*n+3)(!^6))/3 sextic, or 6-factorials).at n=4A053102
• a(n) = 3*a(n-2) + 3*a(n-3), a(0)=1, a(1)=0, a(2)=3.at n=18A099094
• Smallest i such that i*2^(2)-1, ..., i*2^(n+2)-1 are primes.at n=6A101236
• Numbers k such that 4*k-1, 8*k-1, 16*k-1, 32*k-1, 64*k-1 and 128*k-1 are all primes.at n=3A101320
• Numbers k such that 4*k-1, 8*k-1, 16*k-1, 32*k-1 and 64*k-1 are all primes.at n=11A101994
• The n-th lucky number which is the product of exactly n primes (with multiplicity).at n=8A140286
• Numbers with exactly 4 distinct odd prime divisors {3,5,7,11}.at n=30A147577
• Denominators of hypergeometric Cauchy numbers c_(2,n).at n=10A224085
• G.f.: A(x,y) = Sum_{n>=0} exp(-y/(1-n*x)) * y^n/(1-n*x)^n / n!.at n=40A245111
• Denominators of partial sums of the Madhava series for Pi/(2*sqrt(3)) = A093766.at n=5A352398
• a(n) is the least k that has exactly n divisors whose arithmetic derivative is odd.at n=28A363483