21288960

Appears in sequences

• Ramanujan's tau function (or Ramanujan numbers, or tau numbers).at n=23A000594
• Expansion of e.g.f. (1 + 4*x - sqrt(1-8*x))/8.at n=7A052712
• The even bisection of A000594.at n=11A099060
• a(n) = smallest term in A141586 that is divisible by 2^n but not by 2^(n+1).at n=11A141900
• a(n) = number of elements of order n in Mathieu simple group M_24 of order 244823040.at n=22A146074
• a(n) = 4*a(n-1) + 4*a(n-2), n>2, a(0)=1, a(1)=3, a(2)=15.at n=11A155117
• a(n) = 2^(n-1)*(n-1)!*(4*n+1).at n=7A158455
• Table read by rows. Coefficients of Lommel polynomials L(n, m, z) = (Gamma(n + m) / (Gamma(n) * (z/2)^m)) * hypergeom([(1 - m)/2, -m/2], [n, -m, 1 - n - m], z^2) for n = m and descending powers.at n=17A171636
• a(0) = a(1) = 1, a(n) = n! / a(n-2).at n=16A214916
• Table read by rows. T(n, k) = [z^k] LommelR(n, n, 1/z) where LommelR are the Lommel polynomials.at n=27A369117
• a(n) = (2*n)!/a(n-1), with a(0)=1.at n=8A372986
• a(n) = Sum_{k=0..floor(n/3)} (k+1) * 2^k * 3^(n-3*k) * binomial(k,2*(n-3*k)).at n=32A391960
• a(n) = Sum_{k=0..floor(n/3)} (k+1) * 2^k * 3^(n-3*k) * binomial(k,3*(n-3*k)).at n=32A392043