68640

Appears in sequences

• a(n) = n*(n+1)*(2*n+1).at n=32A055112
• Numbers that can be expressed as the difference of the squares of primes in exactly eight distinct ways.at n=13A092004
• Triangle, read by rows, where T(n,k) = n!/(k!*(n-3*k)!*3^k) for n>=3*k>=0.at n=37A118931
• Triangle read by rows: see A128196 for definition.at n=41A126063
• a(n) is found from a(n-1) by dividing by D-1 and multiplying by D, where D is the smallest number that is not a divisor of a(n-1).at n=31A133582
• a(n) = A152800(n+2,2n+1) for n>=0.at n=8A152802
• A partition product of Stirling_2 type [parameter k = -6] with biggest-part statistic (triangle read by rows).at n=17A157396
• Numbers with prime factorization pqrst^5.at n=4A190383
• Molecular topological indices of the graph join C_n + C_n of cycle graphs.at n=19A192848
• Numerators b(n) of Pythagorean approximations b(n)/a(n) to 1/4.at n=9A195563
• Denominators of Pythagorean approximations to 4.at n=2A195619
• a(n) = 6*binomial(n+1,7).at n=9A253947
• Triangle read by rows: T(n,k) is the number of rooted maps with n edges whose core comprises k edges, 1 <= k <= n.at n=32A318106
• Lesser of semi-unitary amicable numbers pair: numbers (m, n) such that susigma(m) = susigma(n) = m + n, where susigma(n) is the sum of the semi-unitary divisors of n (A322485).at n=14A322541
• Lesser of modified exponential amicable pairs.at n=12A323758
• a(n) = (2n)!/(n!*a(n-2)), with a(0) = 1, a(1) = 1.at n=7A372988