20854

Appears in sequences

• Maximal number of regions obtained by joining n points around a circle by straight lines. Also number of regions in 4-space formed by n-1 hyperplanes.at n=27A000127
• Let R(i,j) be the rectangle with antidiagonals 1; 2,3; 4,5,6; ...; each k is an R(i(k),j(k)) and A057046(n)=i(2^n).at n=30A057046
• Number of increasing sequences of n integers x(1),...,x(n) with values in 1..3*n such that x(j) divides x(k) if j divides k.at n=17A180385
• Distance from 2^n to the nearest triangular number.at n=30A233327
• Difference between 4^n and the nearest triangular number.at n=15A238455
• Numbers k such that (56*10^k + 403)/9 is prime.at n=19A294483
• Solution of the complementary equation a(n) = 2*a(n-2) - b(n-1) + n, where a(0) = 4, a(1) = 5, b(0) = 1, and (a(n)) and (b(n)) are increasing complementary sequences.at n=26A295068