21504

Appears in sequences

• Erroneous version of A028368.at n=1A001290
• Degrees of irreducible representations of Held group He.at n=30A003912
• Degrees of irreducible representations of Held group He.at n=29A003912
• Negated coefficients of Chebyshev T polynomials: a(n) = -A053120(n+10, n), n >= 0.at n=6A006975
• Triangle of coefficients in expansion of (1+4x)^n.at n=33A013611
• Expansion of g.f. (1+2*x)/(1-2*x)^2.at n=10A014480
• Number of segments created by diagonals of n-gon.at n=21A014629
• a(n) = (Product_{j=1..n-1} (2^j-1)) * 2^binomial(n+1,2).at n=4A028368
• Low temperature series for spin-1/2 Ising specific heat on 2D square lattice, multiplied by 4.at n=4A029873
• A convolution triangle of numbers obtained from A036070.at n=15A030526
• Weight distribution of [ 48,17,12 ] dual Rao-Reddy code.at n=11A031136
• Weight distribution of [ 48,17,12 ] dual Rao-Reddy code.at n=13A031136
• Numbers k such that the continued fraction for sqrt(k) has even period and if the last term of the periodic part is deleted the central term is 73.at n=31A031571
• Expansion of Sum_{n>=0} (q^n / Product_{k=1..n+4} (1 - q^k)).at n=33A035300
• Expansion of (-1+1/(1-4*x)^4)/(16*x); related to A038846.at n=5A036070
• Triangle whose (i,j)-th entry is binomial(i,j)*4^(i-j).at n=30A038231
• 3-fold convolution of A000302 (powers of 4).at n=5A038845
• Number of partitions satisfying 0 < cn(1,5) + cn(4,5) + cn(2,5) and 0 < cn(1,5) + cn(4,5) + cn(3,5).at n=37A039902
• Denominator of mass (Sum 1/|Aut(H)|) of Hadamard matrices of order 4n.at n=1A048616
• Numbers k such that Sum_{j} p_j = Sum_{j} e_j where Product_{j} p_j^(e_j) is the prime factorization of k.at n=24A054411