51408

Appears in sequences

• Unitary harmonic numbers (those for which the unitary harmonic mean is an integer).at n=19A006086
• Weight distribution of [ 17,9,7 ] code over GF(4).at n=11A014488
• Triangle read by rows: T(n,k) is the number of noncrossing forests with n vertices and k components (1<=k<=n).at n=39A094021
• Triangle read by rows: T(n,k) is the number of noncrossing forests with n vertices and k edges.at n=41A094040
• Triangle read by rows: T(n,k) is the number of permutations p of [n] in which the length of the longest initial segment avoiding the 123-, the 132- and the 321-pattern is equal to k.at n=39A094067
• Consider numbers x,y,z such that UnitarySigma(x) = UnitarySigma(y) = UnitarySigma(z) = 4*(x*y*z)^(1/2)/( x^(1/2) + y^(1/2) + z^(1/2)), x<=y<=z . Sequence gives x .at n=3A144949
• Consider numbers x,y,z such that UnitarySigma(x) = UnitarySigma(y) = UnitarySigma(z) = 4*(x*y*z)^(1/2)/( x^(1/2) + y^(1/2) + z^(1/2)), x<=y<=z . Sequence gives y.at n=3A144950
• Consider numbers x,y,z such that UnitarySigma(x) = UnitarySigma(y) = UnitarySigma(z) = 4*(x*y*z)^(1/2)/( x^(1/2) + y^(1/2) + z^(1/2)), x<=y<=z . Sequence gives z.at n=3A144951
• 1/6 of the number of permutations of 5 indistinguishable copies of 1..n with exactly 5 local maxima.at n=2A152512
• Number of reduced 3 X 3 semimagic squares with distinct nonnegative integer entries and maximum entry n.at n=18A173727
• The Wiener index of the Dutch windmill graph D(6,n) (n>=1).at n=33A180578
• Numbers with prime factorization pqr^3s^4.at n=13A190294
• Number of two-sided n-step prudent walks ending on the northeast corner of their box, avoiding two or more consecutive west steps and south steps.at n=13A190587
• Irregular triangle read by rows: T(n,k) is the number of binary pattern classes in the (7,n)-rectangular grid with k '1's and (7n-k) '0's: two patterns are in same class if one of them can be obtained by a reflection or 180-degree rotation of the other.at n=32A228166
• Irregular triangle read by rows: T(n,k) is the number of binary pattern classes in the (7,n)-rectangular grid with k '1's and (7n-k) '0's: two patterns are in same class if one of them can be obtained by a reflection or 180-degree rotation of the other.at n=37A228166
• a(n) = 6*binomial(n+1,5).at n=13A253945
• Number of integer partitions of n whose omega-sequence has repeated parts.at n=42A325285
• Numbers k such that k and usigma(k) have the same set of prime divisors, where usigma(k) is the sum of unitary divisors of k (A034448).at n=23A329858
• Numbers that are the sum of four third powers in nine or more ways.at n=9A345146
• Numbers that are the sum of four third powers in eight or more ways.at n=32A345152