25584

Appears in sequences

• a(n) = n!*(1 - 1/2 + 1/3 - ... + c/n), where c = (-1)^(n+1).at n=7A024167
• Triangle T(n,k) read by rows giving coefficients in expansion of n! * Sum_{i=0..n} C(x,i) in descending powers of x.at n=43A054651
• Sum_{k|n} a(k)/k! = Sum_{j=1 to n} 1/j, sum on left is over positive divisors k of n.at n=7A067857
• Triangle T(n,k) read by rows, where e.g.f. for T(n,k) is exp(x*y)*log(1+x)/(1-x).at n=28A073480
• a(n) = n!*(2/1 - 3/2 + 4/3 - ... + s*(n+1)/n), where s = (-1)^(n+1).at n=7A080958
• Square array of coefficients of binomial polynomials, read by antidiagonals.at n=35A080959
• Square array of coefficients of binomial polynomials, read by antidiagonals.at n=43A080959
• Starting positions of strings of three 9's in the decimal expansion of Pi.at n=29A083642
• Numbers that have exactly seven prime factors counted with multiplicity (A046308) whose digit reversal is different and also has 7 prime factors (with multiplicity).at n=10A109027
• Expansion of e.g.f. log(1+x)/(1-x)^2.at n=6A109792
• a(n) = 16*n*(n+2).at n=39A114444
• Numbers k such that L(2*k + 1) is prime, where L(m) is a Lucas number.at n=36A117522
• Order of the following permutation on 3n+1 symbols. Write the 3n+1 symbols horizontally into a 3-column grid and read them off vertically, i.e., column after column.at n=45A119980
• Numbers of polypentagons with one internal vertex (see Cyvin et al. for precise definition).at n=13A122744
• Triangle read by rows: T(n,k) is the number of permutations of {1,2,...,n} whose 2nd cycle has k entries; each cycle is written with the smallest element first and cycles are arranged in increasing order of their first elements (n>=1; 0<=k<=n-1). For example, 1432=(1)(24)(3) has 2 entries in the 2nd cycle; 3421=(1324) has 0 entries in the 2nd cycle.at n=41A138771
• Triangle read by rows: coefficients of the alternating factorial polynomial (x+1)(x-2)(x+3)(x-4)...(x+n*(-1)^(n-1)).at n=37A140956
• a(n) = 100*n^2 - n.at n=15A157659
• a(n) = 64*n^2 - 16.at n=19A157913
• a(n) = 400*n^2 - 2*n.at n=7A158316
• a(n) = 256*n^2 - 16.at n=9A158562