227766

Appears in sequences

• a(n) = n*(n-1)*(2*n^2 + 1)/6.at n=29A071245
• a(n) = binomial(n+2,2) * binomial(n+7,2).at n=27A104676
• G.f. A(x) satisfies: A(x) = B(x)^2 - C(x)^2 such that B(x) + I*C(x) = Series_Reversion(x - I*A(x)), where I^2 = -1.at n=4A263531
• a(n) = (n!)^2 * Sum_{k=1..n} 1 / (k * ((n-k)!)^2).at n=6A336291
• Products of 6 distinct primes that are sandwiched between semiprime numbers.at n=26A378627