20842

Appears in sequences

• Atkinson-Negro-Santoro sequence: a(n+1) = 2*a(n) - a(n-floor(n/2+1)).at n=16A005255
• Number of partitions satisfying cn(0,5) <= cn(1,5) + cn(2,5) and cn(0,5) <= cn(4,5) + cn(2,5) and cn(0,5) <= cn(1,5) + cn(3,5) and cn(0,5) <= cn(4,5) + cn(3,5).at n=38A039843
• Numbers n such that 6*10^n + 5*R_n - 4 is prime, where R_n = 11...1 is the repunit (A002275) of length n.at n=19A103038
• Last occurrence of n partitions in A204814.at n=35A205301
• The Wiener index of the zig-zag polyhex nanotube TUHC_6[2n,2] defined pictorially in Fig. 1 of the Eliasi et al. reference.at n=15A227703
• Smallest positive integer k such that k contains all possible pairs of digits when represented in base b = n >= 2.at n=1A249907
• Least inverse of A073454: Smallest m such that m divided by the primes up to m have exactly n repeated residues.at n=22A274320
• Number of n X n 0..1 arrays with every element equal to 1, 2, 4 or 6 horizontally, diagonally or antidiagonally adjacent elements, with upper left element zero.at n=5A302723
• Number of nX6 0..1 arrays with every element equal to 1, 2, 4 or 6 horizontally, diagonally or antidiagonally adjacent elements, with upper left element zero.at n=5A302726
• T(n,k)=Number of nXk 0..1 arrays with every element equal to 1, 2, 4 or 6 horizontally, diagonally or antidiagonally adjacent elements, with upper left element zero.at n=60A302728
• Number of 6Xn 0..1 arrays with every element equal to 1, 2, 4 or 6 horizontally, diagonally or antidiagonally adjacent elements, with upper left element zero.at n=5A302731