26010

Appears in sequences

• Quadrinomial coefficients.at n=16A005719
• Numbers whose base-4 representation contains exactly four 1's and four 2's.at n=16A045109
• Numbers k > 1 such that, in base 9, k and k^2 contain the same digits in the same proportion.at n=1A061663
• Number of partitions of 2n in which all odd parts occur with multiplicity 2. There is no restriction on the even parts.at n=29A101277
• Numbers k such that 7*10^k + 5*R_k - 2 is prime, where R_k = 11...1 is the repunit (A002275) of length k.at n=10A103061
• Number of pyramids in all paths from (0,0) to (3n,0) that stay in the first quadrant (but may touch the horizontal axis), consisting of steps u=(2,1), U=(1,2), or d=(1,-1) (a pyramid is a sequence u^pd^p or U^pd^(2p) for some positive integer p, starting at the x-axis).at n=5A108450
• T(n,k)=Number of pairs of orthogonal (-x,y) vectors of length k*(x+y), where x/y is the n-th rational <= 1, ordered first by y and then x, e.g. 1/1, 1/2, 1/3, 2/3, 1/4, 3/4 ...at n=19A225987
• Number of pairs of orthogonal (-1,4) vectors of length 5*n.at n=1A225991
• Numbers k that are multiples of the digital sum of k-1, k and k+1.at n=37A303068
• Number of integer partitions (of any nonnegative integer) whose sum minus the lesser of their maximum part and their number of parts is n.at n=28A325232
• a(n) is the number of partitions of n with Durfee square of size <= 5.at n=38A330643
• Numbers k such that k and k+1 are both divisible by the square of their largest prime factor.at n=19A354558
• Number of integer partitions of n whose run-sums are not all equal.at n=38A382076
• a(n) is the number of isosceles trapezoids in a triangular grid of side length n.at n=18A389363
• Practical numbers of the form 2*f where f is a product of multiples of Fermat primes (A143512).at n=44A392778