84240

Appears in sequences

• a(n) = floor(n*(n-1)*(n-2)*(n-3)/5).at n=27A011915
• Numbers k that divide the (left) concatenation of all numbers <= k written in base 19 (most significant digit on left).at n=55A029488
• Numbers k such that phi(k) and cototient(k) are squares but k is not in A054755.at n=33A054756
• Ordered m for which m = k^3*a*b*(a^4 - b^4) determine (unique) solution triples(k,a,b), where k=1,2,3,... and (a,b) are coprime pairs, not both odd (i.e., of opposite parity).at n=37A081779
• Numbers k such that phi(k) + k is a fourth power.at n=31A114072
• Number of divisors of n!! (double factorial = A006882(n)).at n=40A114338
• Integers with exactly 100 divisors.at n=2A163816
• a(n) = 65*n^2.at n=35A165798
• Where A174102 sets a new record.at n=43A173570
• Average of amicable pairs (x,y), ordered by the smaller value x given in A002025.at n=12A275315
• Average of amicable pairs (x,y), ordered by the sum x+y given in A259953.at n=12A275316
• Number of partitions of n which can themselves be subdivided into two partitions whose sums differ by 1 at most.at n=45A276107
• Number of minimum and minimal total dominating sets in the n-Mycielski graph.at n=5A303066
• a(n) = 378*n^2 - 54*n (n>=1).at n=14A305070
• Irregular table read by rows: The number of k-faced polyhedra, where k>=4, created when an n-antiprism, formed from two n-sided regular polygons joined by 2n adjacent alternating triangles, is internally cut by all the planes defined by any three of its vertices.at n=54A338808
• a(n) = product of nonzero entries in row n of A235791.at n=26A339577
• Numbers m such that phi(m)*tau(m) is a square but phi(m)/tau(m) is not the square of an integer.at n=31A341940
• a(n) is the least number that has exactly n divisors with the same digit sum.at n=42A359959
• a(n) = Product_{k=0..n} (2^k + 4^(n-k)).at n=3A370014
• Number of minimum dominating sets in the n-Mycielski graph.at n=5A381728