42768

Appears in sequences

• n is equal to the number of 4s in all numbers <= n written in base 6.at n=0A014892
• Euler totient function of Cullen numbers (A002064), n*2^n +1.at n=12A056820
• a(n-1)+k=a(n) => a(n)*k=a(n+1).at n=5A057268
• Values of z in positive integer solutions of x^2 + y^5 = z^3, listed in increasing order of z.at n=32A070067
• Lower triangular array called S1hat(3) related to partition number array A144880.at n=38A144881
• Third column (m=3) of triangle A144881 (S1hat(3)).at n=6A144884
• Triangle T(n, k) = 2*n*binomial(2*n-k, k)*(n-k)!/(2*n-k), with T(0, 0) = 2, read by rows.at n=50A156995
• Numbers k such that phi(tau(k)) = sopf(k).at n=38A173326
• Number of ways to place 6 nonattacking queens on an n X n toroidal board.at n=8A178722
• Numbers with prime factorization pq^4r^5.at n=6A190468
• Number of 2 X 2 matrices having all terms in {1,...,n} and determinant = 0 (mod 3).at n=17A210698
• Number of 2 X 2 matrices having all elements in {0,1,...,n} and determinant = 0 (mod 3).at n=17A211033
• Numbers n that form a Pythagorean quadruple with n', n'' and sqrt(n^2 + n'^2 + n''^2), where n' and n'' are the first and the second arithmetic derivative of n.at n=5A230543
• Zeroless factorials: a(0)=1; thereafter a(n) = noz(n*a(n-1)), where noz(n) = A004719(n) omits the zeros from n.at n=11A243657
• Records in A268642.at n=28A268529
• a(n) = 4*n*(n^2 + 2).at n=21A292022
• Solution of the complementary equation a(n) = 2*a(n-1) - b(n-2), where a(0) = 3, a(1) = 5, b(0) = 1, b(1) = 2, and (a(n)) and (b(n)) are increasing complementary sequences.at n=15A295060
• Numbers that are the sum of 3 nonzero 4th powers in more than one way.at n=5A309762
• Numbers with an even number of prime factors (counted with multiplicity) that can be factored into squarefree semiprimes (A320911) but cannot be factored into distinct semiprimes (A320892).at n=13A320893
• Numbers that are the sum of three fourth powers in exactly two ways.at n=5A344192