39866

Appears in sequences

• a(n) = floor(n*(n-1)*(n-2)*(n-3)/9).at n=26A011919
• Pisot sequences E(5,7), P(5,7).at n=24A020711
• Pisot sequences E(7,10), P(7,10).at n=23A020721
• Numbers k such that 223*2^k+1 is prime.at n=29A032488
• Numbers n such that sigma(n+1)-sigma(n) = -sigma(n)/d(n), where d(n) denotes the number of divisors of n.at n=9A066177
• Number of 5-tuples of primes in arithmetic progression less than 10^n.at n=4A115610
• Triangle read by rows: T(n,k) is the number of unlabeled digraphs on n nodes with k arcs up to reversing the arcs, k=0..n*(n-1).at n=57A126066
• Triangle read by rows: T(n,k) is the number of unlabeled digraphs on n nodes with k arcs up to reversing the arcs, k=0..n*(n-1).at n=65A126066
• a(n) = floor(sqrt(a(n-1)^2 + a(n-2)^2 + a(n-1)*a(n-2))), a(1)=1, a(2)=3.at n=27A128424
• Number of n X 3 integer arrays with each element equal to the number of horizontal and vertical neighbors differing from itself by exactly one.at n=28A266076
• Number of nX2 0..1 arrays with every element unequal to 0, 1 or 2 horizontally, vertically or antidiagonally adjacent elements, with upper left element zero.at n=13A317759
• Number of unlabeled biconnected cubic simple graphs with 2n nodes.at n=9A387146