20220

Appears in sequences

• Number of ternary squarefree words of length n.at n=28A006156
• a(n) = floor(binomial(2*n,n)/3^n).at n=43A024503
• n written in fractional base 4/2.at n=44A024630
• In the list of divisors of n (in base 3), each digit 0-2 appears equally often.at n=11A045811
• a(n)^2 is a square whose decimal expansion digits occur with an exact frequency of 3.at n=7A052095
• Numbers k such that k divides the (right) concatenation of all numbers <= k written in base 16 (most significant digit on right, least significant zeros not written).at n=23A061945
• Denominators of convergents to Pi by Farey fractions.at n=46A063673
• Integers k such that k*28*c + 1 is prime for c = 1, 2, 4, 7 and 14.at n=9A067199
• Numbers k such that k and k^2 use only the digits 0, 2, 3, 4 and 8.at n=26A136885
• Numbers k such that k and k^2 use only the digits 0, 2, 4, 5 and 8.at n=42A136900
• Numbers k such that k and k^2 use only the digits 0, 2, 4, 6 and 8.at n=31A136904
• Numbers k such that k and k^2 use only the digits 0, 2, 4, 7 and 8.at n=35A136906
• Numbers k such that k and k^2 use only the digits 0, 2, 4 and 8.at n=18A136908
• Numbers k such that k and k^2 use only the digits 0, 2, 4, 8 and 9.at n=28A136909
• Numbers consisting of either 2's and 0's or 5's and 0's.at n=30A168541
• Numbers whose decimal expansion contains only 0's and 2's.at n=22A169965
• Numbers k such that k^2 has only digits 0, 4 and 8.at n=20A202170
• Sum of prime divisors of n (with repetition) is one less than the sum of prime divisors (with repetition) of n+1.at n=23A228126
• Number of 4 X n 0..2 arrays with horizontal differences mod 3 never 1, vertical differences mod 3 never -1, and rows and columns lexicographically nondecreasing.at n=16A229447
• Numbers k such that A008475(k)+1 = A008475(k+1).at n=28A333801