26680

Appears in sequences

• Numbers which can be expressed as the product of a number and its reversal in at least two different ways.at n=19A066531
• Numbers k such that the number of divisors of k equals the number of anti-divisors of k.at n=14A073694
• a(n) = 2*a(n-1) + a(n-2) + a(n-3) + a(n-4), with a(0)=1, a(1)=2, a(3)=5, a(4)=13.at n=11A103142
• Long leg B of primitive Pythagorean triangles such that perimeters are Averages of twin prime pairs, q=p+1, a=q^2-p^2, c=q^2+p^2, b=2*p*q, s=a+b+c, s-+1 are primes.at n=15A155174
• a(n) = n*(2*n^2 + 5*n + 13)/2.at n=29A163655
• Number of (n+1)X5 0..1 arrays with rows and columns of permanents of all 2X2 subblocks lexicographically nondecreasing, and all 2X2 permanents nonzero.at n=4A204736
• Number of (n+1)X6 0..1 arrays with rows and columns of permanents of all 2X2 subblocks lexicographically nondecreasing, and all 2X2 permanents nonzero.at n=3A204737
• T(n,k) is the number of (n+1) X (k+1) 0..1 arrays with rows and columns of permanents of all 2X2 subblocks lexicographically nondecreasing, and all 2 X 2 permanents nonzero.at n=31A204740
• T(n,k) is the number of (n+1) X (k+1) 0..1 arrays with rows and columns of permanents of all 2X2 subblocks lexicographically nondecreasing, and all 2 X 2 permanents nonzero.at n=32A204740
• Number of (w,x,y,z) with all terms in {1,...,n} and |w-x| = 2*|x-y| - |y-z|.at n=40A212578
• Least common multiple of 7*n+1 and 7*n-1.at n=33A282286
• Triangle T(n,k) read by rows: coefficients of polynomials P_n(t) defined in Formula section.at n=39A287040