15482880

Appears in sequences

• Ratios of successive terms are 1,2,2,3,4,4,5,6,6,...at n=12A004527
• Triangle whose (i,j)-th entry is binomial(i,j)*4^(i-j)*12^j.at n=31A038242
• Triangle whose (i,j)-th entry is binomial(i,j)*12^(i-j)*4^j.at n=32A038330
• Triangle of coefficients of certain exponential convolution polynomials.at n=22A048786
• Expansion of e.g.f. 3*x/(1 - 2*x).at n=8A052676
• Commuting elements: number of ordered pairs g, h in the group GL(2,Z_n) such that gh = hg.at n=19A070943
• a(n) = 10*(n+1)^3*(n+2)*(5*n+7)^2.at n=5A109120
• Number of n X n real symmetric (+1,-1)-matrices having maximal determinant (=A119003(n)).at n=8A119005
• Number of n X n real symmetric (+1,-1)-matrices having minimal determinant (=A119000(n)).at n=8A119007
• Triangle read by rows: T(n,k) is the number of permutations of {1,2,...,n} having k entries divisible by 3 that are followed by a smaller entry (n>=1, k>=0).at n=33A136718
• E.g.f.: C(x,q) = 1 + Integral S(x,q) * C(q*x,q) dx, such that C(x,q)^2 - S(x,q)^2 = 1, where C(x,q) = Sum_{n>=0} sum_{k=0..n*(n-1)/2} T(n,k)*x^n*y^k/n!, as an irregular triangle of coefficients T(n,k) read by rows.at n=89A322218
• The least number k that is not n-free whose sum of n-free divisors is larger than 2*k.at n=12A387154