-356

Appears in sequences

• Discriminants of quadratic number fields Q(sqrt -n) for n squarefree.at n=55A033197
• a(n) = -a(n-1) - a(n-2) + a(n-3), a(0)=0, a(1)=0, a(2)=1.at n=24A057597
• McKay-Thompson series of class 10E for Monster.at n=69A058101
• a(1) = 1, a(2n) = a(2n-1) + c(n) and a(2n+1) = a(2n) - p(n), where c(n)=A002808(n) and p(n)=A000040(n) are the n-th composite and n-th prime numbers, respectively.at n=44A073891
• Partial sums of A073579.at n=40A077039
• Expansion of 1/(1+2*x^2-x^3).at n=16A077965
• Expansion of 1/(1+2*x^2+x^3).at n=16A077967
• Expansion of (1-x)/(1-x+2*x^2+2*x^3).at n=13A078022
• Expansion of (1-x)/(1+x+2*x^2).at n=17A078050
• Expansion of theta_3(q) / theta_3(q^2) in powers of q.at n=19A080015
• Expansion of f(-q) / f(q) in powers of q where f() is a Ramanujan theta function.at n=19A108494
• Triangle T, read by rows, where all columns of T are different and yet all columns of the matrix square T^2 (A118407) are equal; also equals the matrix inverse of triangle A118400.at n=98A118404
• McKay-Thompson series of class 10E for the Monster group with a(0) = 1.at n=69A132980
• McKay-Thompson series of class 10E for the Monster group with a(0) = 2.at n=69A138516
• Triangle read by rows, T[n,2i-1]=2T[n-1,i],T[n,2i]=2k-1-2T[n-1,i].at n=27A138583
• Irregular triangle, T(n, k) = coefficients of p(x, n), where p(x, n) = (1-2*x)^(n+1) * Sum_{j>=0} j^n*(x/(1-x))^j, read by rows.at n=22A142073
• Expansion of x/(1+x-x^3-x^5-x^6-x^7-x^9+x^11+x^12).at n=33A143606
• Expansion of f(x) * f(x^5) / phi(-x^10)^2 in powers of x where f(), phi() are Ramanujan theta functions.at n=62A147699
• Triangle read by rows: T(n, k) = 2^k - binomial(n, k+1) + 2^(n-k) - binomial(n, n-k+1).at n=60A156862
• Choose smallest m>0 such that the n-th rational prime p ramifies in the imaginary quadratic extension field K = Q(sqrt(-m)); a(n) = discriminant(K).at n=23A220861