131670

Appears in sequences

• A triangle of numbers related to triangle A049325.at n=51A049410
• Numbers k such that phi(k) < k/5.at n=15A066765
• First occurrence (*2) of n in A088627 - or - least number that yields n different primes if you factorize it in all possible ways in two factors and add these factors.at n=29A091350
• Integers that can be expressed as a product of triangular numbers in 3 different ways.at n=6A110904
• Sums of the products of n consecutive triples of numbers.at n=11A135037
• a(n) = n*binomial(n+4, 4).at n=18A174002
• Numbers with prime factorization pqrstu^2.at n=9A189985
• The number of triangles in an equipotential triangle divided by medians into n rows of smaller triangles.at n=25A210687
• Triangle where the g.f. for row n equals d^n/dx^n (1+x+x^2)^n / n! for n>=0, as read by rows.at n=40A220178
• Central terms in rows of triangle A220178.at n=4A222051
• Triangle read by rows: T(n,k) = binomial(2*n,k)*Stirling2(2*n-k,n).at n=25A226703
• Numbers k satisfying gcd(k^2, sigma(k^2)) > sigma(k), where sigma is the sum-of-divisors function.at n=36A322154
• Numbers k such that N = k^6 is a twin rank (cf. A002822: 6N +- 1 are twin primes).at n=31A326236
• Numbers k with a record number of divisors d < sqrt(k) such that d + k/d is prime.at n=12A331665
• a(n) is the number of subsets of {1..n} that contain exactly 1 odd and 4 even numbers.at n=43A333321
• Numbers with a record number of deficient divisors.at n=30A335542
• a(n) = n! / (a(n-1) a(n-2) a(n-3)), where a(0) = a(1) = a(2) = 1.at n=19A372995
• a(n) is the first number with a total of exactly n 3's in the decimal digits of its divisors.at n=39A387464