27028

Appears in sequences

• Numbers n such that n | 9^n + 7^n + 5^n + 3^n.at n=22A063455
• Triangular numbers which are the sum of two squares.at n=31A073613
• a(n) = smallest k where (10^k+1)=0 mod prime(n)^2, or 0 if no such k exists.at n=50A086981
• Triangular numbers with palindromic indices.at n=32A089717
• Number of partitions of 2n in which both odd parts and parts that are multiples of 3 occur with even multiplicities. There is no restriction on the other even parts.at n=27A101230
• a(n) = 3 + floor((2 + Sum_{j=1..n-1} a(j))/5).at n=50A120172
• Number of nondecreasing integer sequences of length 16 with sum zero and sum of absolute values 2n.at n=14A158150
• Cyclops triangular numbers.at n=9A160717
• a(n) = binomial(F(n), 2) where F(n) = A000045(n).at n=13A191797
• Primitive numbers in A229307.at n=23A229311
• Numbers n with the property that the symmetric representation of sigma(n) has four parts, each of width one and two regions meet at the center of the Dyck path.at n=16A264104
• a(n) = A000217(A000217(n)+1).at n=21A267707
• Number of parts in all partitions of n with largest multiplicity five.at n=32A320375
• Number of separable partitions of n in which the number of distinct (repeatable) parts is > 1.at n=39A325716
• Even composite integers m such that U(m)^2 == 1 (mod m) and V(m) == 7 (mod m), where U(m)=A004187(m) and V(m)=A056854(m) are the m-th generalized Lucas and Pell-Lucas numbers of parameters a=7 and b=1, respectively.at n=41A337782
• Number of skew shapes in a 3 X n rectangle with no empty rows or columns.at n=21A362153