176715

Appears in sequences

• Tritriangular numbers: a(n) = binomial(binomial(n,2),2) = n*(n+1)*(n-1)*(n-2)/8.at n=35A050534
• Consider 2n tennis players; a(n) is the number of matches needed to let every possible pair play each other.at n=16A062346
• Solutions to phi(x + omega(x)) = phi(x) + d(x), where phi() = A000010(), d() = A000005() and omega() = A001221().at n=13A063868
• Numbers k such that k, 2*k and 4*k are balanced numbers (A020492).at n=30A076376
• Smallest triangular number divisible by exactly n triangular numbers.at n=13A076983
• a(n) = smallest number which can be expressed as sum of d consecutive positive integers in exactly n ways (where d>0 is a divisor of the number).at n=34A082637
• Numbers n such that sigma(n) = 6*phi(n).at n=20A104900
• Triangle read by rows: T(n,k) is the number of set partitions of {1,2,...,n} (or of any n-set) having k blocks of even size (0<=k<=floor(n/2)).at n=39A124322
• a(n) = (9/2)*(n-1)*(n-2)*(n-3).at n=35A134171
• a(n) = smaller member of n-th pair of distinct, positive, triangular numbers whose sum and difference are also triangular numbers.at n=22A185129
• Triangular numbers that are the product of two triangular numbers greater than 1.at n=32A188630
• Triangular numbers that are the product of three distinct triangular numbers greater than 1.at n=25A225440
• Numbers k such that (25*10^k - 37) / 3 is prime.at n=27A276698
• Least positive integer k with exactly n odd divisors greater than sqrt(2*k).at n=29A281008
• Triangular numbers that can be represented as a sum of two distinct triangular numbers, and as a product of two triangular numbers greater than 1.at n=14A295768
• Triangular numbers that can be represented as a product of two triangular numbers greater than 1, and as a product of three triangular numbers greater than 1.at n=12A295769
• a(n) is the smallest number that has exactly n binary palindrome divisors (A006995).at n=27A355716
• a(n) is the least number k that has exactly n divisors <= sqrt(k) of the form 4*j+3.at n=16A379683
• a(n) is the least number k that has exactly n divisors <= sqrt(k) of the form 4*j+1.at n=15A379693