19784

Appears in sequences

• Super-4 Numbers (4 * n^4 contains substring '4444' in its decimal expansion).at n=15A032744
• A Wallis pair (x,y) satisfies sigma(x^2) = sigma(y^2); sequence gives y's for indecomposable Wallis pairs with x < y (ordered by values of x).at n=36A075769
• Numbers k such that 5^k - 2 is prime.at n=11A109080
• Triangle read by rows: T(n,k) is the number of secondary structures of size n (n>=0) having k stacks of length 1 (k>=0).at n=59A202838
• Number of -2..2 arrays x(i) of n+1 elements i=1..n+1 with set{t,u,v in 0,1}((x[i+t]+x[j+u]+x[k+v])*(-1)^(t+u+v)) having four, five, six or seven distinct values for every i,j,k<=n.at n=8A211584
• Numbers k such that 12*3^k + 1 is prime.at n=16A216889
• Number of partitions p of n such that 3*min(p) is a part of p.at n=39A238590
• p-INVERT of the triangular numbers (A000217), where p(S) = 1 - S - S^2.at n=7A289797
• Triangle read by rows: T(n,k) is the number of 4-ary strings of length n with k indispensable digits, with 0 <= k <= n.at n=41A330509
• a(n) = Sum_{k=1..n} 3^(floor(n/k) - 1).at n=9A345029