73920

Appears in sequences

• [ n(n-1)(n-2)(n-3)/17 ].at n=35A011927
• There are exactly n integer-sided triangles of area a(n).at n=40A051586
• a(n) = ceiling(n!/d(n!)).at n=10A055981
• Sixth (unsigned) column of triangle A062140 (generalized a=4 Laguerre).at n=3A062263
• Least m such that A067513(m) = n.at n=41A067846
• Highly composite triangular numbers: triangular numbers where the number of divisors increases to a record.at n=13A076711
• Smallest triangular number divisible by exactly n triangular numbers.at n=15A076983
• Triangular numbers that set a new record for number of triangular divisors.at n=10A084260
• Triangular numbers > 0 with a prime signature that has not occurred earlier.at n=37A085076
• Triangle read by rows, where T(n,k) is the coefficient of x^n*y^k in f(x,y) that satisfies f(x,y) = 1/(1-x)^2 + xy*f(x,y)^2.at n=51A086614
• Triangle read by rows: T(n,k) is the number of Dyck paths of semilength n, having k ddu's [here u = (1,1) and d = (1,-1)].at n=40A091894
• Numbers that can be expressed as the difference of the squares of primes in exactly seven distinct ways.at n=20A092003
• Row sums of triangle A093922.at n=27A093925
• Triangular numbers which are 10-almost primes.at n=1A101744
• Triangular numbers that are sums of two consecutive primes.at n=38A111163
• When the n-th term of this sequence is added to or subtracted from the square of the n-th prime of the form 4k + 1 (i.e., A002144(n)), the result in both cases is a square.at n=27A114200
• Triangular numbers whose digit reversal is the product of 2 palindromes greater than 1.at n=41A115702
• Triangular numbers that are sandwiched between two semiprimes; or triangular numbers t such that t-1 and t+1 are both semiprime.at n=20A121898
• Triangle T, read by rows, where T(n,k) = A008544(n-k)*C(n,k) where A008544 equals the triple factorials in column 0.at n=22A136216
• Least number k such that sigma_2(k) >= 2^n.at n=32A141847