19839

Appears in sequences

• Numbers k such that the period of the continued fraction for sqrt(k) contains exactly 19 ones.at n=15A031787
• Number of bracelet structures using a maximum of five different colored beads.at n=11A056355
• G.f. is the continued fraction: A(x) = 1/[1 - x/[1 - (x-x^2)/[1 - (x^2-x^4)/[1 - (x^3-x^6)/[1-... - (x^n-x^(2n))/[1 - ... ]]]]]]].at n=24A099823
• a(n) = Sum_{i=1..n} (prime(i)^n - 1)/(prime(i) - 1).at n=4A124271
• an=n-th smallest integer m=p1*p2*p3, product of 3 odd primes such that d+2m/d are all primes for d dividing 2m.at n=15A128278
• a(n) = floor(sqrt(pi(2^n))).at n=33A133498
• Transform of the finite sequence (1, 0, -1, 0, 1) by the T_{1,1} transformation (see link).at n=11A159330
• Numbers m such that m*reversal(m) contains every decimal digit exactly once.at n=3A178929
• Array read by antidiagonals: T(n,k) is the number of color patterns (set partitions) in an unoriented cycle of length n using k or fewer colors (subsets).at n=115A320748