19370

Appears in sequences

• Number of equivalence classes of binary sequences of primitive period n.at n=21A002730
• Number of n-step spirals on hexagonal lattice.at n=20A006777
• Partition numbers rounded to nearest integer given by the Hardy-Ramanujan approximate formula.at n=35A050811
• Number of primitive (period n) step cyclic shifted sequences using exactly two different symbols.at n=21A056424
• Numbers that can be represented as a sum of two distinct nontrivial prime powers in three or more ways.at n=20A225104
• Numbers which are the sum of two squared primes in exactly three ways (ignoring order).at n=7A226562
• Numbers k that are the product of four distinct primes such that x^2+y^2 = k has integer solutions.at n=32A248712
• Positions of 2's in A264977; positions of 3's in A277330.at n=55A277712
• Triangle read by rows: T(m,n) (1 <= n < m) is the number of moves of an (m,n)-leaper (a generalization of a chess knight) until it can no longer move, starting on a board with squares spirally numbered from 1. Each move is to the lowest-numbered unvisited square. T(m,n) = -1 if the path never terminates.at n=47A323749
• Successive records of function f(x) = log(abs(pi(x) - R(x)))/log(x) where pi(x) is the number of primes <= x and R(x) is Riemann's prime counting function.at n=53A353055
• Expansion of (1/x) * Series_Reversion( x*(1-x)^5/(1-x+x^2) ).at n=5A387840