72390

Appears in sequences

• Triangular numbers k*(k+1)/2 such that A068865(k) = k*(k+1)/2.at n=28A068866
• a(n) = n*(n+1)*(n^2+n+1)/2.at n=19A110450
• Triangular numbers that are sandwiched between two semiprimes; or triangular numbers t such that t-1 and t+1 are both semiprime.at n=19A121898
• Number of edges in the Hasse diagram of the poset of conjugacy classes of subgroups of the symmetric group.at n=12A218925
• Integers m such that A342805(m) = m+3.at n=34A342806
• Triangular numbers which are products of five distinct primes.at n=21A357590
• Triangular numbers that are sandwiched between two squarefree semiprimes.at n=17A375384