28731

Appears in sequences

• Nearest integer to 4 * Pi * n^3 / 3.at n=19A002101
• a(n) = T(2n,n), T given by A026780.at n=7A026781
• a(n) = T(n, floor(n/2)), T given by A026780.at n=14A026786
• Numbers k such that k^2 is palindromic in base 13.at n=25A029998
• Sums of distinct powers of 13.at n=21A033049
• Divide natural numbers in groups with prime(n) elements and add together.at n=17A034956
• Numbers whose base-13 representation has exactly 5 runs.at n=0A043660
• Numbers n such that n^3 is palindromic in base 13.at n=9A046247
• a(n) = (n^2 - n + 1)*(n^2 + n + 1).at n=13A059826
• Sum of squares of divisors of square numbers.at n=12A065827
• Integers n such that 2*10^n + 81 is a prime number.at n=19A110920
• Ceiling(4/3*Pi*n^3).at n=19A135973
• Jordan function ratio J_6(n)/J_2(n).at n=12A194532
• E.g.f. satisfies: A(x) = Sum_{n>=0} (-1)^n/n! * Sum_{k=0..n} (-1)^k*C(n,k)*(1 + x*A(x)^k)^k.at n=5A195947
• Central polygonal numbers that are nontrivially the product of two central polygonal numbers.at n=15A203173
• Numbers n such that n contains exactly 5 digits, all distinct, and n^2 contains exactly 9 distinct digits.at n=27A204691
• Numbers arising in computing the Turan function of cycles of length 4.at n=43A217004
• Array t(n,k) of sum of successive even powers of primes, where t(n,k) = sum_(j=0..k-1) prime(n)^(2j), with n>=1 and k>=0, read by ascending antidiagonals.at n=39A241855
• Least integer k such that the n-th prime of form m^2+1 divides the composite number k^2+1.at n=30A255675
• Ulam numbers k such that k/3 is also an Ulam number.at n=41A287212