84480

Appears in sequences

• Ramanujan's tau function (or Ramanujan numbers, or tau numbers).at n=7A000594
• Coefficients of Chebyshev T polynomials: a(n) = A053120(n+8, n), n >= 0.at n=8A006974
• a(n) = sigma(sigma(...(sigma(n))...)) / n, where sigma (A000203) is iterated until a multiple of n is reached.at n=12A019295
• Numbers n such that n divides the (right) concatenation of all numbers <= n written in base 21 (most significant digit on right).at n=27A029514
• Theta series of (putative) extremal 2-modular even lattice in dimension 40.at n=3A034604
• Ramanujan's tau function (or tau numbers (A000594)) for 2^n.at n=3A035174
• a(n) = (2/3) * 4^n * binomial(3*n, n).at n=3A036909
• 8-fold convolution of A000302 (powers of 4).at n=4A054338
• A sequence related to Ramanujan's tau function.at n=28A055978
• a(n) = Product_{i=1..n} phi(i) * Sum_{i=1..n} 1/phi(i) where phi is the Euler totient function A000010(n).at n=9A067578
• Numbers k that divide tau(k)*sigma(k).at n=46A071707
• Number of 4-ary Lyndon words of length n over Z_4 with trace 2 and subtrace 2.at n=11A074412
• Let P(k,X) = Product_{i=1..2*k} (X-1/cos(Pi*(2*i-1)/(4*k)) ) which is a polynomial with integer coefficients. Sequence gives array of coefficients for P(k,X).at n=71A075615
• Array of coefficients in Zagier's polynomials P_(n,0)(x).at n=39A075733
• Triangle read by rows: T(n,k) is the number of Dyck paths of semilength n, having k ddu's [here u = (1,1) and d = (1,-1)].at n=39A091894
• The even bisection of A000594.at n=3A099060
• Number of walks between adjacent nodes on C_5 tensor J_2.at n=10A101501
• a(n) = binomial(n+3,4)*4^4.at n=7A120054
• a(n) = product of the positive integers k, k <= n, such that the positive integers <= k and coprime to k are also coprime to n.at n=21A124675
• Coefficient table for Chebyshev polynomials T(2*n,x) (increasing even powers x, without zeros).at n=40A127674