18660

Appears in sequences

• a(n) = 3^(n-1) - 2^n + 1 (essentially Stirling numbers of second kind).at n=9A028243
• Triangular array a(n,k) = (1/k)*Sum_{i=0..k} (-1)^(k-i)*binomial(k,i)*i^n; n >= 1, 1 <= k <= n, read by rows.at n=47A028246
• Numbers k such that 45*2^k+1 is prime.at n=22A032372
• Decimal part of a(n)^(1/5) starts with a 'nine digits' anagram.at n=5A034280
• Numbers having four 4's in base 8.at n=11A043440
• Triangle read by rows, giving T(n,k) = number of k-member minimal ordered covers of a labeled n-set (1 <= k <= n).at n=37A049055
• Number of k-simplices in the first derived complex of the standard triangulation of an n-simplex. Equivalently, T(n,k) is the number of ascending chains of length k+1 of nonempty subsets of the set {1, 2, ..., n+1}.at n=37A053440
• Values of m such that N=(am+1)(bm+1)(cm+1) is a 3-Carmichael number (A087788), where a,b,c = 1,2,29.at n=3A064251
• Number of (n,3) Freiman-Wyner sequences.at n=13A097925
• Triangle read by rows, 0 <= k <= n, T(n,k) = Sum_{j=0..n} A(n,j)*binomial(n-j,k) where A(n,j) are the Eulerian numbers A173018.at n=52A130850
• Values of z in solutions (x,y,z) to the Diophantine equation x^3-x^2+y^3-y^2=z^3-z^2, with 1<x<y<z arranged in order of increasing x.at n=23A138669
• Expansion of the exponential generating function 1 - log(1 - x*(exp(z) - 1)), triangle read by rows, T(n,k) for n >= 0 and 0 <= k <= n.at n=58A142071
• Triangle read by rows: The n-th derivative of the logistic function written in terms of y, where y = 1/(1 + exp(-x)).at n=47A163626
• Number of length 6 nonnegative integer arrays starting and ending with 0 with adjacent elements unequal but differing by no more than n.at n=9A205343
• Number of (w,x,y,z) with all terms in {1,...,n} and 2|w-x|>n+|y-z|.at n=20A212689
• Triangle read by rows: the positive terms of A163626.at n=26A249163
• Second differences of ninth powers (A001017).at n=2A255179
• Square array A(n,k) (n>=1, k>=1) read by antidiagonals: A(n,k) is the number of n-colorings of the prism graph Y_k on 2k vertices.at n=57A277443
• Triangle T(n, k) read by rows: T(n, k) = S2(n, k)*k! + S2(n, k-1)*(k-1)! with the Stirling2 triangle S2 = A048993.at n=48A285867
• Numbers m > 0 that have a divisor d > 1 with binomial(m+d, d) == 1 mod m.at n=33A290040