292320

Appears in sequences

• E.g.f. (1-x)^3/(1-4x+3x^2-x^3).at n=6A052603
• Expansion of e.g.f. (1-x)/(1-3*x+x^3).at n=6A052693
• Number of permutations of {1,...,n} avoiding adjacent step pattern up, down, up, down, down.at n=9A177528
• G.f. L(x) satisfies: L(x) = L(exp(x)-1)*(1-exp(-x))/x = Sum_{n>=1} a(n)*x^n/(n!*(n+1)!).at n=7A180609
• Numbers other than prime powers divisible by the sum of the squares of their prime divisors.at n=31A190882
• Numbers n having a proper divisor d such that sigma(n) - k*d = k*n. Case k = 4.at n=27A291458
• Primitive 4-abundant numbers: Numbers k such that sigma(k) > 4k (A068404) all of whose proper divisors d are 4-deficient numbers (having sigma(d) < 4d).at n=22A307114
• Irregular triangle read by rows: coefficients of q-Eulerian polynomials of Type B.at n=21A333273
• Numbers m such that the equation m = k*sigma(k) has more than one solution.at n=14A337873
• Triangle T(n,k) defined by Sum_{k=1..n} T(n,k)*u^k*x^n/n! = Product_{j>0} ( exp(j*x^j/(1 - x^j)) )^u.at n=22A338865
• Expansion of e.g.f. (1/24) * ( log(1 + x) / (1 - x) )^4.at n=5A389003
• Triangle read by rows: T(0,0) = 1, T(n,0) = 0 for n > 0; T(n,k) = (1/(k-1)!) * Sum_{j=k..n} binomial(n,j) * Stirling1(j,k) * (n-j+k-1)!, 0 <= k <= n.at n=49A389008
• Primitive terms of A023198: numbers k with the property sigma(k)/k >= 4 that are not divisible by any other number with that property.at n=24A392936