47520

Appears in sequences

• Values of phi(k) when phi(k) = phi(k+1).at n=36A003275
• Theta series of E_6 lattice.at n=23A004007
• Area of more than one Pythagorean triangle.at n=36A009127
• Number of 2n-bead balanced binary strings of fundamental period 2n, rotationally equivalent to reversed complement, inequivalent to reverse and complement.at n=12A045669
• a(n) = Product_{i = 0..n-1} ((3*i+1)!*(6*i)!*(2*i)!)/((4*i)!*(4*i+1)!).at n=3A049504
• E.g.f. (1-x)/(1-4x+2x^2).at n=5A052590
• (2^n+2)*n!.at n=6A052626
• Nonprime numbers k such that k | sigma_3(k) + phi(k)^3.at n=18A055970
• a(n) = A062401(A065391(n)): phi(sigma(m)) peak values for numbers m (listed in A065391) at which those peaks are first reached.at n=26A065392
• Numbers n such that sigma(n)^2 > 9*sigma_2(n) where sigma_2(n) is the sum of squares over the divisors of n.at n=25A068378
• Product of all n - d, where d < n and d is a divisor of n.at n=11A072513
• Binomial transform of reflected tetranacci numbers A074058: a(n)=Sum((-1)^k Binomial(n,k)*A074058(k),(k=0,..,n)).at n=13A075129
• Numbers k such that phi(k-1) + phi(k+1) = sigma(k)/2.at n=5A076648
• Duplicate of A072513.at n=11A080499
• Numbers k such that 2^k - 1 is divisible by (k-1).at n=30A087965
• Array used for numerators of g.f.s for column sequences of array A078741 ((3,3)-Stirling2).at n=8A089517
• UO-sigma multiperfect numbers: n such that A069184(n)/n is an integer.at n=6A092356
• 5-infinitary perfect numbers: numbers k such that 5-infinitary-sigma(k) = 2*k.at n=3A097464
• Structured snub cubic numbers.at n=19A100150
• T(n,k) is the number of permutations of [n] with maximum descent k, T(n,k) for n >= 0 and 0 <= k <= n, triangle read by rows.at n=60A130477