370230

Appears in sequences

• Triangular numbers that are sandwiched between two semiprimes; or triangular numbers t such that t-1 and t+1 are both semiprime.at n=32A121898
• a(n) is the smallest triangular number that is a multiple of the product of the members of the n-th pair of twin primes.at n=5A344886
• 32*a(n) is the denominator of the squared circumradius of a cyclic quadrilateral with sides n, n+1, n+2, n+3.at n=39A351697
• Triangular numbers which are products of six distinct primes.at n=6A362758
• Triangular numbers that are sandwiched between two squarefree semiprimes.at n=30A375384