69952

Appears in sequences

• Expansion of 1/((1-2*x)*(1-6*x)).at n=6A016129
• Triangle of Legendre-Stirling numbers of the second kind T(n,j), n >= 1, 1 <= j <= n, read by rows.at n=29A071951
• Number of primitive Pythagorean triangles with perimeter equal to A002110(n), the product of the first n primes.at n=22A077177
• Triangle of scaled second column sequences of (k,k)-Stirling2 arrays.at n=29A091039
• a(1)=1; for n > 1, a(n) = Sum_{1<=j<n, gcd(j,n)=1} a(j)*a(n-j).at n=12A096421
• Triangle read by rows of Legendre-Stirling numbers of the second kind.at n=34A191935
• Round(-1/n + 1/log((2n+1)/(2n-1))).at n=17A227513
• a(n) = 2*a(n-1) - a(n-3) + a(ceiling(n/2)), where a(0) = 1, a(1) = 1, a(2) = 1.at n=21A298404
• a(n) = p(1,n), where p(x,n) is the strong divisibility sequence of polynomials based on sqrt(3) as in A327321.at n=6A329009
• a(n) = Sum_{-n<i<n, -n<j<n, gcd{i,j}=2} (n-|i|)*(n-|j|).at n=25A331772
• Numerator of ratio n*sigma(A003961(n)) / sigma(n)*A003961(n), where sigma is the sum of divisors of n, and A003961 shifts the prime factorization of n one step towards larger primes.at n=63A341526