103488

Appears in sequences

• Numbers k such that phi(sigma(k)) + sigma(phi(k)) = 2k.at n=12A066950
• Product of elements in the simple continued fraction for (1+1/n)^n.at n=6A071599
• The number of bijections f:{1,...,n}->Z/nZ such that f(ab)=f(a)+f(b) whenever all three function values are defined.at n=22A179989
• Logarithms (cf. A179989) f:{1,...,n}->Z/nZ such that either (i) n is odd or (ii) n is even and f(m) is even whenever m divides n/2.at n=22A179990
• Numbers with prime factorization pqr^2s^6.at n=21A190474
• Denominators a(n) of Pythagorean approximations b(n)/a(n) to e.at n=6A195541
• Number of n X 2 0..3 arrays with some element plus some horizontally or vertically adjacent neighbor totalling three exactly once.at n=4A269091
• Number of nX5 0..3 arrays with some element plus some horizontally or vertically adjacent neighbor totalling three exactly once.at n=1A269094
• T(n,k)=Number of nXk 0..3 arrays with some element plus some horizontally or vertically adjacent neighbor totalling three exactly once.at n=16A269097
• T(n,k)=Number of nXk 0..3 arrays with some element plus some horizontally or vertically adjacent neighbor totalling three exactly once.at n=19A269097
• T(n,k)=Number of nXk 0..3 arrays with some element plus some horizontally, diagonally or antidiagonally adjacent neighbor totalling three exactly once.at n=19A269214
• Number of 5Xn 0..3 arrays with some element plus some horizontally, diagonally or antidiagonally adjacent neighbor totalling three exactly once.at n=1A269218
• G.f.: 3F2([1/7, 2/7, 4/7], [1/2, 1], 2401 x).at n=2A275052
• Triangle read by rows. T(n, k) = binomial(n, k)^2 * CatalanNumber(k).at n=42A367178
• a(n) is the first number with a total of exactly n 4's in the decimal digits of its divisors.at n=42A386391