89424

Appears in sequences

• n is equal to the number of 4s in all numbers <= n written in base 6.at n=7A014892
• Numbers k such that the least term in the periodic part of the continued fraction for sqrt(k) is 26.at n=22A031704
• Numbers k such that sigma(k^2 + 1) == 0 (mod k).at n=44A067719
• a(n) = T(n)^2 - n^2, where T(n) is a triangular number.at n=24A085740
• a(n) = 529*n^2 + 23.at n=13A158631
• a(n) = 169*n^2 + n.at n=22A173275
• Numbers with prime factorization pq^4r^5.at n=16A190468
• The number of n-permutations having precisely two cycles whose lengths are relatively prime.at n=7A194364
• Sum of absolute values of real and imaginary parts of the coefficients in the expansion of 1 / (1 - x - I*x^2), where I^2=-1.at n=32A218137
• 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=27A320893
• a(n) = n! * [x^n] Product_{k=1..n, gcd(n,k) = 1} (1 + x^k/k).at n=9A338439
• Numbers k such that k, k^2-1 and k^2+1 are all fine, where a number m is fine if its prime factors are all less than m^(1/3).at n=22A345896
• Triangular array read by rows: T(n,k) is the number of cubic n-permutations possessing exactly k cycles; n >= 0, 0 <= k <= n.at n=47A348191