23250

Appears in sequences

• Expansion of (1-x)^(-1)/(1 + x - x^2 + x^3).at n=18A077902
• Number of permutations satisfying -k<=p(i)-i<=r and p(i)-i not in I, i=1..n, with k=3, r=3, I={-2,1,2}.at n=19A079983
• Smallest m such that A132575(m) = n.at n=42A132576
• a(n) = (n+6)*(n+1)*(n^2 + 7*n + 16)/4.at n=15A168538
• Constant term in the reduction of the polynomial 1+x+x^2+...+x^n by x^3->x^2+x+1. See Comments.at n=19A192804
• a(1) = least k such that 1/3 < H(k) - 1/3; a(2) = least k such that H(a(1)) - H(3) < H(k) - H(a(1)), and for n > 2, a(n) = least k such that H(a(n-1)) - H(a(n-2)) > H(k) - H(a(n-1)), where H = harmonic number.at n=14A225605
• Numbers k such that 477*2^k+1 is prime.at n=33A319487
• a(n) = Product_{d|n} (d*sigma(d)) where sigma(k) = the sum of the divisors of k (A000203).at n=24A324980
• Numbers k such that k and uphi(k) have the same set of prime divisors, where uphi is the unitary totient function (A047994).at n=23A329859
• a(n) = Product_{d|n} lcm(d, sigma(d)) where sigma(k) is the sum of divisors of k (A000203).at n=24A334805
• a(n) = (n^2+n+1)*(n^2+n)*n^2.at n=5A356768
• Numbers k such that k - A067666(k) is a square.at n=41A386304