837760

Appears in sequences

• a(n) = (n+1)*(n+2)^2*(n+3)^2*(n+4)*(3*n+5)/720.at n=13A107908
• If X_1,...,X_n is a partition of a 2n-set X into 2-blocks then a(n) is equal to the number of 4-subsets of X containing none of X_i, (i=1,...,n).at n=31A130810
• A partition product of Stirling_2 type [parameter k = 2] with biggest-part statistic (triangle read by rows).at n=32A157402
• Numbers k for which k * gcd(sigma(k), A003961(k)) is equal to sigma(k) * gcd(k, A003961(k)), where A003961 shifts the prime factorization one step towards larger primes, and sigma is the sum of divisors function.at n=9A349745